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UTA / Biology / BIOL 2458 / What is the difference between endocrine and exocrine glands?

What is the difference between endocrine and exocrine glands?

What is the difference between endocrine and exocrine glands?


School: University of Texas at Arlington
Department: Biology
Course: Anatomy and Physiology II
Professor: Timothy henry
Term: Fall 2018
Cost: 50
Name: A&P ll
Description: Final study guide
Uploaded: 12/05/2018
25 Pages 29 Views 2 Unlocks

Anatomy and Physiology Final Study Guide

What is the difference between endocrine and exocrine glands?

Chapter 16: Endocrine System 

∙ Are hormone responses in the endocrine system faster or slower than the  nervous system?

o Slower but longer lasting

∙ What is the difference between endocrine and exocrine glands? o Endocrine: produce hormones, lack ducts

o Exocrine: have ducts, produce non-hormonal substances (sweat,  saliva)

∙ Is the hypothalamus a neuroendocrine organ? (also called “the boss”) o Yes

∙ What are the different types of chemical messengers of the endocrine  system?

o Hormones, Paracrine, Autocrines

∙ Why paracrine and autocrines aren’t considered hormones? o They are only short distance signals

How do hormones change target cell activity?

∙ List the two classes of hormones and their characteristics.

o Amino acid- protein derivatives

o Steroid- made from cholesterol

∙ Hormones bind to what?

o Receptors on target cells

∙ How do hormones change target cell activity?

o Membrane potential changes

∙ What is the difference between water-soluble hormones and lipid-soluble  hormones?

o Water-soluble hormones include amino acid hormones and require a  second messenger protein to get into the cell membrane

o Lipid-soluble protein are steroid hormones and thyroid hormones bind  to intracellular receptors inside the cell membrane; don’t require a  second messenger protein

What are the 2 types of second messenger systems?

Don't forget about the age old question of Why are people messed up if assumptions are true?

∙ What are the 2 types of second messenger systems? Describe their  processes.

o cAMP-

 Hormone binds to receptor  If you want to learn more check out Does the new testament begin with the four gospels?

 Receptor binds to G-protein

 G-protein activates adenlyate cyclase

 Adenylate cyclase converts ATP to cAMP

 cAMP phosphorylates other enzymes by activating or inhibiting  them

o PIP2

 G-protein activates phospholipase C

 Phospholipase C activates and splits into two proteins

∙ Diaglycerol (DAG)- activates protein kinases

∙ Inositol trisphosphate- cause Ca ions to release from  

intracellular storage sites

∙ Describe the process of gene activation with intracellular receptors? o Hormone enters the cell and binds to intracellular receptor

o The hormone-receptor complex enters the nucleus

o The complex attaches to a specific region of DNA

o Binding initiates transcription of the gene mRNA

o mRNA directs protein synthesis

∙ Hormone release is controlled by negative feedback We also discuss several other topics like What are the 5 types of mining?

∙ Name the 3 types of endocrine gland stimuli?

o Hormonal stimuli, Humoral Stimuli, Neural Stimuli

∙ What is up-regulation vs down-regulation?

o Up-regulation: when more receptors are on the hormone due to low  levels

o Down-regulation: when there are fewer receptors on the hormone in  response to high levels

∙ Half life of a steroid hormone: long laster; Half life of amino acid hormone:  short lasting

∙ Know what permissiveness, synergism, and antagonism are

o Permissiveness: one hormone can’t function without the other o Synergism: two hormones work together and produce a stronger  response

o Antagonism: two hormones have the opposite effects of each other ∙ What are two major lobes of the pituitary gland and what are they composed  of?

o Anterior and Posterior

∙ Be able to know the hormones released by both posterior and anterior  pituitary (FLAT PiG).

o Posterior: Oxytocin and Antidiuretic Hormone We also discuss several other topics like What was the earliest form of print media?
If you want to learn more check out What is the function of the endoplasmic reticulum in a cell?

o Anterior: Follicle stimulating hormone, leutinizing hormone,  

Adenocorticotropin hormone, thyroid hormone, prolactin, growth ∙ Understand what the thyroid gland, parathyroid gland, adrenal gland, pineal  gland, pancreas, gonads, and placenta does

∙ Know the homeostatic imbalances of the glands described above ∙ Know what hormones are secreted by adipose tissue, GI tract, Heart, Kidneys, skeleton, skin, and thymus

Chapter 17: Blood 

∙ What are the three functions of blood? If you want to learn more check out What are the main characteristics of eastern woodlands tribes?

o Transport, regulation, protection

∙ What elements are made up of blood

o Plasma (55%) Formed elements (45%), buffy coat

∙ What are found in the formed elements?

o RBCs, WBCs, platelets

∙ What percentage of water is plasma?

o 90%

∙ What are the two types of leukocytes (white blood cell)?

o Granulocytes: neutrophil, eosinophil, basophil

o Agranulocytes: monocyte, lymphocyte

∙ What are the structural characteristics of erythrocytes (red blood cells)? o RBCs have a plasma membrane but no nucleus and no organelles o Contain a protein called spectrin that allows the RBC to change shape  and pass through the capillaries

o It’s biconcave shape allows for maximum surface for gas exchange o Over 97% hemoglobin which allows for transport of respiratory gases ∙ What are the function of red blood cells?

o Transportation of oxygen and carbon dioxide

∙ What is hemoglobin composed of?

o 2 alpha helixes, 2 beta chains

∙ What is hematopoiesis?

o Formation of all blood cells

∙ Erythropoiesis: formation of RBCs

∙ What are the function of leukocytes (WBCs)

o Defend the body against disease

∙ What are platelets?

o Fragments of larger cells called megakaryocytes

∙ What is the process that helps prevent blood loss when a blood vessel is  ruptured or destroyed?

o Hemostasis

∙ Be able to know the steps of hemostasis

o 1. Vascular spasm

o 2. Platelet plug formation

o 3. Coagulation

∙ What will 15-30% of blood loss do to the human body

o Pallor and weakness

o More than 30% could be fatal

∙ What are the different blood groups called?

o AB, A, B,O

o AB: universal recipient

o O: Universal donor

∙ What is the importance of diagnostic blood tests?

o Reveals info on a person’s health

o Low hematocrit  anemia

o Blood glucose tests check for diabetes

o Leukocytosis  infection

Chapter 18: The Heart 

∙ What two systems make up the cardiovascular system?

o Pulmonary and Systemic Circuts

∙ What side of the heart pumps oxygen-rich blood? Oxygen-poor blood? o Right: Oxygen-poor

o Left: Oxygen-rich

∙ What is the pericardium

o A two layered sac where the heart sits in

∙ What are the 3 layers of the heart? (Outer to Inner)

o Epicardium, Myocardium, Endocardium

∙ What are the four chambers of the heart?

o Aria (right and left atrium) and Ventricles (right and left ventricles) ∙ Which chambers are the receiving chambers? Pumping chambers? o Receiving chambers : Atria

o Pumping chambers: Ventricles

∙ What is the largest artery of the body

o Aorta

∙ Be able to know blood of the heart

o Right atriumTricuspid ValveRight ventriclePulmonary valveLeft  atrium Mitral valve (bicuspid valve)Left ventricle  Aorta

∙ What is chordae tendinae

o Help prevent backflow and are attached to atrioventricular valves (AV  valves)

∙ Know the anatomy of a cardiac muscle

∙ What is the main difference between skeletal and cardiac muscle? o Ca2+ binds to troponin causing filaments to slide

∙ Be able to know the Electrical events of the heart (Intrinsic & Extrinsic) Setting the Basic Rhythm: The Intrinsic Conduction System 

∙ The presence of gap junctions and the intrinsic conduction system helps  maintain the independent, and coordinated activity of the heart ∙ The system consist of noncontractile cardiac cells which help to initiate  and distribute impulses through the heart

Action Potential Initiation by Pacemaker Cells

∙ Cardiac pacemaker cells can depolarize spontaneously resulting in the pace  of the heart

o Have unstable resting potential, called pacemeaker potentials, that  depolarizes and drifts slowly towards the threshold in a continuous  manner.

o These pacemaker potentials create action potentials and cause  rhythmic contractions

o 3 Parts of an Action Potential

 1. Pacemaker Potential- Depolarization occurs because of the  opening of Na+ channels and K+ channels.

 2. Depolarization- Once pacemaker potential reaches threshold  Ca2+ channels open; the influx of Ca2+ produces the rising phase  of the action potential

 3. Repolarization- Ca2+ channels inactivate which triggers the  falling phase of the action potential; K+ channels opens and K+  

leave the cell

Sequence of Excitation

∙ Cardiac pacemaker cells are typically found in the sinoatrial and  atrioventricular nodes

∙ When the SA node and AV node are not working the AV bundle, right and left  bundle branches, and the Purkinje fibers can sometimes act as pacemakers ∙ 1. Sinoatrial Node

o Located in the right atrium

o Generates 75 impulses per minute

o The heart’s pacemaker because no other regions of the heart has a  faster deporalization rate than the SA node

o The heart’s sinus rhythm, which determines heart rate

∙ 2. Atrioventricular (AV) node

o Located above the tricuspid valve

o Has a delay of 0.1 second which allows for the atria to complete their  contraction before the ventricles can contract

 Due to the small diameters of the fibers and few gap junctions o AV node conducts impulses slower than other parts of the system due  to this delay

∙ 3. Atrioventricular (AV) bundle

o Located in the superior part of the interventricular septum

o Only electrical connection between the atria and ventricles

∙ 4. Right and left bundle branches

o AV bundles splits into two paths – right and left bundle branches o Run along the interventricular septum near the apex of the heart o Excite the cells of the interventricular septum

∙ 5. Subendocardial conducting network (Purkinje fibers)

o Long strands of barrel-shaped cells that have few myofibrils

o Ventricular depolarization relies heavily on Purkinje fibers, and on cell  to cell transmission of impulses via gap junctions

o The fibers are more elaborate on the left ventricle because it is bigger  than the right ventricle

Modifying the Basic Rhythm: Extrinsic Innervation of the Heart 

∙ The autonomic nervous system (ANS) is responsible for modification and  variability of the heart beat

∙ Sympathetic NS increase rate and force of the beat; Parasympathetic slows  the heart

∙ Heartbeat modification controlled by ANS via cardiac centers o Cardioacceleratory center- send signals to sympathetic neurons;  innervate SA and AV nodes, heart muscles, and coronary arteries o Cardioinhibitory center- parasympathetic signals via vagus nerve to  decrease rate; inhibiton of SA and AV nodes

Action Potentials of Contractile Cardiac Muscle Cells

∙ Contractile muscle fibers make of the bulk of heart muscle and is responsible  for the pumping activity of the heart

∙ 1. Depolarization

o Fast voltage-gated Na+ channels open; Na+ rushes into the sarcolemma from the extracellular fluid (ECF); Na+ influx initiated by positive  feedback cycle ( -90mV to +30mV); influx of Na+ is brief

∙ 2. Plateau phase

o Na+ depolarization triggers slow Ca2+ channels to open; Ca2+ enters the sarcolemma and a plateau in the action potential develops because  Ca2+ causes the muscles cells to contract

∙ 3. Repolarization

o After 200 ms repolarization occurs (action potential falls rapidly); Ca2+ channels inactivate and voltage-gated K+ channels open and K+ ions  leave the cell. Ca2+ is pumped back into SR and extracellular space

∙ The plateau phase is important because it ensures that the contractions are  complete so that blood is pumped out efficiently from the heart, and so that  tetanic contractions cannot occur

∙ Be able to know the phases of the cardiac cycle

o 1. Ventricular filling, 2. Ventricular Systole, 3. Isovolumetric Relaxation ∙ Be able to know what valves close that make the heart sounds o Lub-dup

o First sound: AV valves closing

o Second sound: SL valves closing

∙ Be able to know the process of regulation of pumping

Ch. 20: Lymphatics System 

∙ What are the lymphatic vessels responsible for?

o Responsible for bringing escaped fluid back into the blood stream to be returned to the blood

∙ Lymphatic vessels is a one-way system and takes to lymph towards the heart ∙ Where does the transport of lymph began?

o Lymphatic capillaries

∙ Why are lymphatic capillaries permeable?

o Their endothelial cells are not joined tightly; overlap each other to form minivalves

∙ What are lacteals?

o Specialized lymphatic capillaries that transport absorbed fat from small intestine to the bloodstream; produce chyle (milky,wihite, fatty lymph) ∙ Lymph flows from lymphatic capillaries to what structure?

o Collecting lymphatic vessels

∙ What are the five major areas that lymphatic trunks drain?

o Paired lumbar, bronchomediastinal, Subclavian, jugular, intestinal ∙ What are the two large ducts found in the thoracic region of the body? o Right lymphatic duct and Thoracic duct

∙ What are the types of lymphoid cells? Functions?

o Lymphocytes

 T-cells: maintain immune response; directly attack and destroy  infected cells

 B-cells: protect body against antigens; produce antibodies

o Macrophages: phagocytize foreign substances; help activate T cells o Dendritic cells: capture antigens and return them back to the lymph  nodes

o Reticular cells- produce stroma, reticular fiber that supports other cells  in lymphoid organs and tissues

∙ What are the two types of lymphoid tissues? ( Be able to know the functions) o Diffuse lymphoid tissue and Lymphoid follicles (nodules)

∙ What categories are the lymphoid organs grouped into?

o Primary lymphoid organs- sites where T and B cells mature (Know their  locations)

o Secondary lymphoid organs- sites where the mature lymphocytes does their jobs

∙ What is the most important organ from the secondary lymphoid organs  category? Lymph nodes

∙ What are the two protective functions of lymph nodes: 1. Cleanse the lymph;  acts as a filter 2. Immune system activation

∙ Be able to know the pathway of lymph flow in the lymph nodes ∙ What are the two components the spleen is composed of ?

o White pulp: made up of mostly lymphocytes; responsible for immune  functions

o Red pulp: destruction site for RBCs

∙ What are the three main locations where MALT (Mucosa-associated lymphoid  tissues) are found?

o Tonsils, Peyer’s patches, appendix

Chapter 21: Immune System 

∙ What are the two general types of immunity

o Non-specific and Specific

∙ What are the barriers associated with non-specific immunity

o Barriers, Inflammation, Fever, Phagocytosis, and Antimicrobial  substances

∙ What are the two types of specific immunity

o Cell-mediated immunity

o Antibody-mediated immunity

o **Be able to know the process of both types***

∙ What do complement proteins enhance?

o Phagocytosis, Cytolysis, Inflammation

∙ What happens when a pathogen first enters the body?

o Macrophages will phagocytize the pathogens while NK cells will enter  and allow for cytolysis to occur

∙ What is immunological memory?

o When the T and B cells have memory of an encounter of a specific  antigen that will help the body have quicker response in fighting the  antigen

∙ What is the first line of defense?

o Physical: skin, eye structures, mucous membranes

o Chemicals: sweat, keratin, lysozyme, gastric juice, tears

∙ What are the types of antimicrobial substanes?

o Interferon- produced by lymphocytes infected by a virus,; enter new  cells and help prevent viral replication

o Complement protein- group of inactive plasma proteins; formation  triggered by antigen-antibody complex

∙ What is the process of inflammation?

o 1. Vasodilation/Increased Blood Permeability

 Triggered by histamine that is released by mast cells and  basophils

 Blood that flows to the area which result in redness, heat, and  swelling

o 2. Neutrophil……

 Neutrophils and monocytes flow to the injured area and  

monocytes remove microbe with phagocytosis

 Pus is formed from the interstitial fluid and debris and lingers in  the injured area until the infection passes

o 3. Tissue repair

 Fibrinogen forms a thread-like spread over the injured site  forming a clot. A scab then develops and new cells under the  scab mend the wound to help the tissue heal

∙ Know the table of Interlukins (ILs) *Aranda’s said this*

∙ What lymphocytes are involved in cell-mediated immunity? T- lymphocytes ∙ Where are CD4 and CD8 receptors found on?

o CD4-helper T cells

o CDD8- cytotoxic T cells

∙ Know the role of CD4 T cells

o Recognize foreign antigens when presented with an APC that is  associated with MHC-II protein

o Activation: Helper T cell antigen must bind with the antigen with the  MHC-II protein; Co-stimulation occurs to making bind between MHC-II  and the helper T cell bind tighter

o Proliferation and Differentiation: After activation, the T cells will  become effector T cells and some will become memory T cells ∙ Know the role of CD8 T cells

o Recognize foreign antigens when presented with the MHC-I protein o Activation: Tumor cells, foreign tissue transplant cells, virus-infected  cell are recognized by cytotoxic T cells. Co-stimulation from the close  association of the infected cell and cytotoxic T cells helps complete  activation

o Proliferation and differentiation: Clone and differentiate into effector  cytotoxic T cells and memory cytotoxic T cells

∙ What are the 2 methods that cytotoxic T cells use to eliminate infected T  cells?

o Perforin-induced cytolysis: Perforin is released by cytotoxic T cells and  puncture holes on target cell membranes causing target cell to burst o Lymphotoxin induced cell death- Lymphotoxin released by cytotoxic T  cells degrade the DNA of the target cell and leads to cell death of the  target cell

∙ What lymphocyte is used during antibody-mediated immunity? B lymphocytes

∙ Be able to know what occurs during antibody-mediated immunity o B cells have receptors (immunoglobulins) which are similar to the  antibodies that daughter plasma cells will secrete once activated m o B cells bind to an unprocessed antigen; must activate when co stimulated by nearby T-cells in lymphatic tissue

o Activation: B cells can act as APC; antigen found inside of B cell via  digestion; MHC-II and antigen fragments are combine; excocytosis  occurs and the antigen-MHC-II complexes are stuck on the B cell  membrane: A helper T cell with the correct antigen receptors bind to  the antigen on the B cell which triggers the release of IL-2 activating it

o Clonal selection (proliferation and differentiation): some B cells will  become plasma cells and some will become memory B cells

o Antibodies help fight infection in a variety of ways

 Antibodies can neutralize virus and toxins

 Antibodies can immobilize bacteria by attaching themselves on  it

 Antibodies can cause agglutination precipitation of antigen  

(forming antigen complexes); removed by phagocytes

 Antibodies can result In the activation of complement proteins  Antibodies can surround microbes in a process called  

opsonization which enhance phagocytosis

∙ What are the four methods of acquiring adaptive immunity> o Naturally acquired active immunity

o Naturally acquired passive immunity- antibodies transferred from mom to baby in milk during breast-feeding

o Artificially acquired active immunity- antigens are introduced into the  body through vaccines\

o Artificially acquired passive immunity-  

∙ What is the difference between positive selection and negative selection? o Positive selection: T-cell must recognize self-MHC proteins

 If recognized: apoptosis  

o Negative selection: T-cell must not recognize self-antigen

 If T cell recognizes self-antigen: apoptosis

Chapter 22: The Respiratory System

∙ Be able to know the types of epithelium in the upper and lower respiratory  tract

o *Refer to Slides 33-34*

∙ Know the difference between the respiratory zone and the conducting zone o Respiratory zone: areas where there is gas exchange

o Conducting zone: any passageway that conditions air

∙ Know all the Laws  

o Dalton’s Law  

o Boyle’s Law ( how it relates to inhalation and exhalation)

o Henry’s Law

∙ Know the difference between normal and forceful breathing

o Forceful breathing requires the contraction of the diaphragm, and the  internal and external intercostals

∙ Why doesn’t the alveoli collapse?

o Secretion of surfactant

∙ Know the three processes of respiration

o Ventilation

o External respiration

o Internal respiration

∙ What is ventilation-perfusion coupling?

o As a response to hypoxia the lungs will vasoconstrict to allow change  the direction of blood from poorly ventilated areas to well ventilated  areas

∙ Know the composition of the respiratory membrane

∙ Know the process of transport of Oxygen and Carbon Dioxide in the blood ∙ What are the factors that affect the affinity of Hb to oxygen? o Partial pressure of Oxygen and Carbon dioxide

 High Carbon dioxide levels lead to unloading of oxygen cells

 Low levels of carbon dioxide increases affinity

o pH  

 Low pH leads to unloading of oxygen cells

 High pH increases affinity of Oxygen to hemoglobin

o Temperature

 Increase temp unloading of oxygen

 Lower temp increases affinity

o Hemoglobin type

o BPG (bisphosphoglycerate)

 High levels of BPG  unloading of oxygen

∙ Cortical influences

o Allowed individual to have voluntary control of our breathing rate and  depth

 Example: choose to hold our breath or taking an extra breath ∙ Chemoreceptors (central and peripheral) monitor levels of oxygen and carbon dioxide

Chapter 23: Digestive System

Gastrointestinal Tract (GI) vs Accessory Structures

∙ GI Tract: esophagus, stomach, small intestine, large intestine, rectum ∙ Accessory structures: teeth, tongue, salivary glands, liver, gall bladder,  pancreas

o Not part of GI tract

o Contribute to food processing

Layers Of GI Tract

∙ Serosa Muscularis ( aids in mixing and propulsion of food substances)  Mucosa

Autonomic Nervous System

∙ Parasymphathetic- on signal for digestion; Sympathetic- off signal for  digestion

Mouth: Mechanical and Chemical Digestion

∙ Mechanical: mastication (chewing) of food  bolus formed ( for ease of  swallowing ( deglutition))

∙ Chemical: salivary amylase breaks down the starches in the mouth  (polysaccharides to disaccharides)


∙ Bolus turns into chime

∙ Functions:

o Mixing (churning) of food to form chyme

o Reservoir for food before it’s released to small intestine

o Secretes gastric juice

o Secretes gastrin (promotes digestion) into the bloodstream ∙ Fed State vs. Fasted State

o Fed State- allows for HCl production

∙ Peristalsis: uses longitudinal and circulatory muscles to digest food Pancreas, Liver, Gallbladder

∙ Not part of GI tract

∙ Pancreas

o Produce enzymes that digest macronutirents ( which are the  macromolecules)

o Sodium bicarbonate is produced here to act as a buffer for stomach  acid

∙ Liver

o Makes bile (emulsify fats)

o Responsible for carbs, lipid, and protein metabolism

o Excretion of bilirubin ( what makes feces a brown color)

o Activation of Vitamin D

o Histology

 Composed of hepatocytes; very vascularized (because of the  veins)

 Nutrient-rich blood

 Processes nutrients for digestive tract

 Nutreint-rich blood from deO2 blood from hepatic vein Hepatic  sinusoids Central vein  Hepatic vein Inferior vena cava Right atrium

∙ Gallbladder

o Stores bile until needed

Small Intestine

∙ 90% of absorption and digestion takes place in the small intestine ∙ Intestinal juices in the small intestine helps to absorb chyme via villi in the SI ∙ Brush border enzymes are found on the microvilli, on the surface of  absorptive cells, which aid in the digestion of food products

∙ Mechanical Digestion: Peristalsis (propulsive reactions) and Segmentaion  ( Localized contractions (food doesn’t move))

∙ Chemical Digestion: Digestion of macronutrients

Large Instestine

∙ Functions

o Haustral churning, peristalsis, mass peristalsis ( Mechanical Digestion)  o Synthesis vitamin B and K; bacteria in the colon breaks down proteins  into amino acids (Chemical Digestion)

o Absoroption of water, ions, vitamins

∙ Chemical Digestion occurs through the actions of bacteria

∙ Allows for defecation  

o Happens because of distension

Chapter 24: Metabolism and Nutrition 

Metabolic Reactions

∙ Catabolic Reactions- breaking down into simpler molecules (decomposition) ∙ Anabolic Reactions- building simpler molecules to complex molecules  (synthesis)

Energy Transfer

∙ Oxidation-Reduction  

∙ Oxidation: removal of electrons or hydrogen ions from an atom or molecule

∙ Reduction: addition of electrons to a molecule

Carbohydrate Metabolism

∙ A.k.a Glucose metabolism

∙ Glucose passes through membrane via facilitated diffusion (uses  transporters)

o Transporters: GluT transporter

o The transporters are controlled by the hormone insulin which signals  the insertion of GluT4 molecules

∙ Oxidation of glucose  Cellular respiration

o 1. Glycolysis (10 steps)

o 2. Acetyl coA formation ( Citric acid cycle)- 8 steps

o 3. Krebs Cycle

o 4. Electron Transport Chain (ETC)

∙ Substrate level phosphorylation- substrates makes ATP 

∙ Oxidative phosphorylation- occurs in the electron transport chain (ETC) ∙ Glycogenesis- creation of glycogen 

o Stimulated by insulin 

∙ Glycogenolysis- breaking down of glycogen 

o Stimulated by glucagon and epinephrine 

∙ Gluconeogenesis- creation of glucose from other macronutrients o Stimulated by cortisol, glucagon, and thyroid hormone 


∙ 1. Glycolysis (anaerobic pathway b/c of no presence of oxygen) o Occurs in the cytosol

o Glucose splits into 2 3-carbon molecules of pyruvic acid

o GlucoseGlucose-6-phosphateFructose 1,6-biphosphate

Glycerolaldehyde 3-phosphate

o What happens to pyruvic acid depends on whether or not there is a  presence of oxygen

 Pyruvic acid:  

∙ Oxygen converted to acetyl coA (coenzyme A)

o The formation of acetyl coenzyme A occurs in the  


∙ No oxygen converted to lactic acid ( addition of 2  

hydrogen atoms)

∙ 2. Krebs Cycle (or Citric Acid Cycle)

o 8 reactions

o Function: production of reduced coenzymes

o Occurs in the matrix of mitochondria

o Glucose molecule is completely oxidized

o 2 ATP (energy) molec ules produced; remaining energy from the acetyl  groups are transferred to reduced coenzymes

o 2 FADH2, 6 NADH, 2 GTP, 2 ATP 

∙ 3. Electron Transport Chain (ETC)

o Reduced coenzymes used to generate ATP

o Inner membrane of mitochondria

o When the reduced enzymes are oxidized the energy is used to pump  Hydrogen ions across the inner mitochrondria membrane

o Water is formed as hydrogen ions are released and combine with  oxygen

o H+ ions form a concentration gradient between inner membrane and  matix of the mitochondria

o Concentration of hydrogen ions provides force to produce ATP  molecules

o As hydrogen diffuses down its gradient it passes through protein that  make ATP

o Chemiosmosis- Process of producing ATP using movement of  hydrogen ions down its gradient through the protein ATP synthase

Lipid Metabolism

∙ Most lipids are nonpolar(hydrophilic) and must be combined with proteins  (lipoproteins) to pass through the membrane.

o Lipoproteins are produced by the liver and intestines

∙ Four classes of Lipoproteins

o Chylomicrons- transport dietary lipids to adipose tissue

 Adipose tissue removes triglyceride from chylomicrons and  

VLDLs (98% of body energy reserves)

o Very-low-density lipoproteins (VLDLs)- transport triglycerides from hepatocytes to adipocytes

o Low-density lipoproteins (LDLs)- carry 75% of the total cholesterol  in our blood and deliver it to cells

o High-density lipoproteins (HDLs)- remove excess cholestorerol  from body cells and the blood and transports it to the liver for removal  High cholesterol levels lead to a high risk of coronary artery  disease

Video Notes: Lipid Metabolism

∙ When digested, lipids are hydrolyzed into fatty acids and glycerol ∙ Fatty acid/glycerol can be oxidized to generate ATP or used to produce  triglycerides for energy storage which gets stored in adipose tissue ∙ Lipid catabolism begins with lipolysis; lipids must be broken down before  they can be oxidized to generate ATP in the Krebs cycle

o Lipolysis is stimulated by epinephrine, norepinephrine cortisol, thyroid  hormones, and human growth hormone

∙ After lipolysis, fatty acids and glycerol are oxidized in different ways o Fatty acids undergo beta oxidation- a series of reactions that form  acetyl coA from a 2 carbon fragment of a fatty acid chain and  

coenzyme A

o Acetyl coA enters the Krebs cycle which produced reduced coenzymes  ( NADH + H+) that are used to generate ATP in the electron transport  chain (ETC)

o When beta oxidation is excessive, 2 carbon fatty acid fragments are  converted into ketone bodies; overproduction of acidic ketone bodies  results in ketosis which can lead to ketoacidosis of the blood

o After lipolysis, glycerol is converted into pyruvic acid, pyruvic acid is  used to form acetyl coA which enters Krebs cycle, the reduced  

coenzymes that are produced are used to generated ATP in the ETC o Glycerol is moved into the glycolytic pathway and converted into  glucose which is called gluconeogenesis ( stimulated by glucagon  and cortisol)

∙ Lipid anabolism is known as lipogenesis (also called fed state or absorptive  state), which is stimulated by insulin, and takes place in liver and adipose  cells

o Triglycerides are synthesized from acetyl coA and glucose molecules; o Acetyl coA molecules are produced from amino acids, glucose and  ketone bodies and these molecules are then converted into fatty acids; o Glucose is converted into glycerol through the formation of  

glyceraldehyde phosphate;  

o Through a series of anabolic reactions, glycerol and fatty acids become triglycerides and phospholipids

Protein Metabolism

∙ Proteins can functions enzymes, involved in transportation, act as antibodies,  helps clot blood, serve as hormones, or are part of muscle fibers

Video Notes: Protein Metabolism

∙ During digestion, proteins are hydrolyzed into amino acids and transported  into the bloodstreams

∙ Amino acids and proteins are not stored: they are oxidized to generate ATP or synthesized into new proteins

∙ If there are excess amounts of amino acids they are converted into  carbohydrates or lipids for storage

∙ Protein catabolism (deamination)

o Small amounts of amino acids are converted into substances that will  be oxidized into carbon dioxide and water in order to generated ATP o Amino acids in the liver cells must undergo oxidative deamination:  Amino group (NH2) is removed

 Highly toxic ammonium ions (NH4) are formed and combine with carbon dioxide which converts the ammonium ions into less  

toxic urea molecules which are released in the urine

o The deaminated acids are then transported into the Krebs cycle to be  oxidized into carbon dioxide and water

 Prior to entering the Krebs cycle, they need to be converted into  intermediate products ( pyruvic acid, acetyl coA, carbonic acids)  When they are in the Krebs cycle they are oxidized into reduced  coenzymes, and then are used in the electron transport chain to  generate ATP

o Amino acids are used to form other energy molecules through the  formation of acetyl coA and pyruvic acid

 Glucose are formed during gluconeogenesis

 Triglycerides are formed during lipogenesis

 Ketone bodies are formed during ketogenesis

o The energy in these molecules are used to produced reduced  coenzymes and generate ATP

∙ Protein anabolism produces new proteins through formation of peptide  bonds between amino acids

o This process places on the ribosomes in all cells; covalent bonds form  between amino acids during process of translation which continues  until a polypeptide has been formed

Key Molecules at Metabolic Crossroads

∙ Glucose 6-phosphate, Pyruvic acid, and acetyl coenzyme A are important in  metabolism 

 ∙      Glucose 6-phosphate is involved in: 

o Synthesis of glycogen and nucleic acids

o Glycolysis

o Release of glucose into the bloodstream

 ∙      Pyruvic acid is involved in: 

o Production of lactic acid and alanine

o Gluconeogenesis

 ∙      Acetyl coenzyme A is involved in: 

o Synthesis off lipids

o Helps 2-carbon acetyl groups enter Krebs cycle

Metabolic Adaptions

∙ During the absorptive state, or fed state, glucose is readily available ∙ In the post absorptive state digestion is done and all the energy needs are  met by fuels already in the body

∙ Starvation is going without food or inadequate food for weeks or months ∙ Fasting is going without food for several hours or few days

∙ During fasting and starvation, an increase in the production of ketone bodies  is the most dramatic metabolic change that occurs due to the catabolism of  fatty acids increasing 

Heat and Energy Balance

∙ Metabolic rate: overall rate which metabolic reactions use energy o Greatly determines body temp

∙ Basal metabolic rate (BMR): metabolic rate measured when the body is in a  quiet, resting and fasting state

∙ Negative feedback loops maintain normal body temperature ∙ A group of neurons in the hypothalamus serve as the body’s thermostat ∙ When the body overheats, heat promoting center is inhibited, body begins to  sweat to cool down the body

∙ When body temp is low, heat-promoting center is stimulated; shivering  occurs ( due to muscles contracting) and hormones are released to increase  tissue metabolism

Chapter 25: Urinary System 

∙ Kidneys are paired organs

∙ Urinary system helps maintain homeostasis through the maintenance of ions, blood volume, and ions

∙ 3 External Layers of the Kidneys (Superficial to Deep)

o Renal Fascia- anchors kidney and adrenal gland to their surrounding  structures

o Perirenal Fat Capsule (Adipose Capsule)- fatty mass that  surrounds the kidney; protects and cushions

o Renal Capsule (Fibrous capsule)- a thick fibrous layer that  surrounds the kidneys; prevents infections; continuous with ureter ∙ Internal Anatomy of the Kidneys

o Renal cortex- most superficial region of inside the kidneys

o Renal medulla- deep to the cortex

o Renal pyramids- found within the renal medulla; cone-shaped tissue  masses; formed entirely of urine-collecting tubules and capillaries o Renal Columns- separate the renal pyramids; anchor the cortex

Renal Blood and Nerve Supply

Blood Supply 

∙ Kidneys are always continuously cleansing the blood; have a rich blood  supply

∙ Receive about 25% of resting cardiac output

Nerve Supply 

∙ Renal Plexus is a network of autonomic nerve fibers and provide the nerve  supply of the kidneys and ureters

∙ Regulate renal blood flow through the kidneys

25.2: Nephrons

∙ Nephron are the functions and structural unit of a kidney

o Renal corpuscle- filters the blood plasma

 Glomerulus- contain fenestrated (with many pores) capillaries  that allow large amounts of solutes that are protein-free to pass  from the blood to the glomerular capsule

∙ Fed by Afferent arteriole and drained by the Efferent  


 Glomerular (Bowmans) capsule- 2 layers (visceral and  

parietal) contain a visceral layer of podocytes (create filtration  

slits) that wrap around the glomerular capillaries

∙ Filtrate collects between the visceral and parietal layers

o Renal Tubule and Collecting Duct- modifies the filtrate  

 3 Major Parts: Proximal convoluted tubule (PCT), Nephron Loop,  Distal convoluted tubule (DCT)

 Proximal Convoluted Tubule (PCT)

∙ Made up of cuboidal epithelial cell with large  

mitochondria; also contain microvilli to increase surface  

area for water and solute reabsorption  

 Nephron Loop (or Loop of Henle)

∙ Consist of the descending loop and ascending loop

 Distal Convoluted Tubule (DCT)

∙ Cuboidal epithelial, lack microvilli

 Collecting Duct

∙ 2 Cell Types:

o Principal cells- sparse, short microvilli; maintain  

the body’s water and Na+ balance; receptors for  

ADH and aldosterone

o Intercalated cells- cuboidal cells; abundant  

microvilli; helps manage blood pH

∙ 2 Classes of Nephrons

 o Cortical nephrons:  

 80-85% of nephrons are cortical nephrons

 Contain short loops of henle that dip into the outer medulla  which is in the cortex

 Create urine with and osmolarity that is similar to blood

 Glomerular (Bowman’s) capsuleProximal convoluted tubule Descending nephron loopAscending nephron loopDistal  

convoluted tubule (drains into collecting duct) 

 o Juxtamedullary nephrons: 

 Contain longer loops of henle that penetrate deep into the  


 Receive blood from peritubular capillaries and vasa recta

 Ascending limb and thick and thin segments

 Enable kidney’s ability to produce urine that is concentrated

 Glomerular (Bowman’s) capsuleProximal convoluted tubule Descending nephron loopthin Ascending nephron loop Thick  

ascending loop of the nephron loop Distal convoluted tubule  

(drains into collecting duct) 

Overview: Three Major Renal Processes

∙ 1. Glomerular filtration

o Occurs in the renal corpuscle; produces cell and protein-free filtrate o Water,glucose, amino acids ,ions ( calcium, potassium,phosphorus),  urea, creatnine

o Blood cells and proteins not filtered

∙ 2. Tubular reabsorption

o Selectively moving substances from the filtrate back into the blood o Occurs in the renal tubules and collecting ducts

o Glucose, water, amino acids, and ions are reabsorbed

o PCT: Glucose, amino acids, bicarbonate, water, sodium, chloride,  potassium, magnesium, phosphate, calcium, urea ; LOH: (descending):  water. (ascending): permeable to ions, sodium, chloride, potassium;  DCT: sodium, water ( under influence of aldosterone), calcium (PTH),  bicarbonate; CT: sodium water (ADH), urea

∙ 3. Tubular secretion

o Moving substance from blood into the filtrate

o PCT: Uric acid, antibiotics, diuretics; LOH: urea (sometimes); DCT:  potassium, hydrogen ions

o Occurs in the renal tubules and collecting ducts

NOTE: *** Filtrate is the fluid that contains everything found in blood plasma except  proteins*****

NOTE: ***Urine contains the unneeded substances (excess salts and metabolic  wastes) *****

Water, urea,creatnine, NaCl

Urine Formation: 

Step 1: Glomerular Filtration: 

∙ Glomerular filtration: passive process where hydrostatic pressure forces fluids and solutes through a membrane

∙ The filtration membrane is porous and allows water and small molecules to  move out of the glomerulus

∙ Blood hydrostatic pressure is the pressure that promotes filtration o Chief force that pushes water and solutes out of the blood and across  the filtration membrane

o Has a pressure of 55 mmHg ( really high compared to other pressures  in capillary beds)

∙ Capsular hydrostatic pressure and blood colloid osmotic pressure inhibit  filtrate formation by opposing hydrostatic pressure in glomerular capillaries o Capsular hydrostatic pressure is the pressure exerted by filtrate in the  glomerular capsule

o Blood colloid osmotic pressure is the pressure exerted by proteins in  the blood that “sucks” water into the capillaries

 ∙      Regulation: 

o Kidneys need a constant glomerular filtration rate (GFR) to make  filtrate and maintain homeostasis

o Increase in GFR increases urine output , decrease in blood volume  and blood pressure

o Decrease in GFR  decrease urine output, increase in blood volume and blood pressure

∙ Controlled by: Renal Autoregulation, Neural Regulation, Hormonal Regulation  o Renal Autoregulation 

 Uses two different mechanisms

 ∙      Myogenic Mechanism 

o Similar to the property of vascular smooth muscle

contracts when stretched, relaxed when not

o High blood pressure stretches smooth  

muscleafferent arterioles constrictsblood flow  

into glomerulus restricted and GFR level  


o Low blood pressuredilation of afferent arterioles

glomerular hydrostatic pressure increases

 ∙      Tubuloglomerular Feedback Mechanism  

o Controlled by the macula densa cells of  

juxtaglomerular complex

o Macula densa respond to high levels of filtrate NaCl

by releasing ATP and other vasocontricting  

chemicals to constrict the afferent arteriole which  

reduces blood flow into glomerulus

o Low levels of filtrate NaCl inhibits ATP from macula  

densa cells resulting in vasodilation of afferent  

arterioles more blood flow into glomerulus

 o Neural Regulation 

 Symphathetic nerve fibers release norepinephrine and  

epinephrine (from adrenal medulla) when blood pressure falls.  Smooth muscle constricts peripheral resistance increases

blood pressure returns to normal

 Baroceptor reflex causes afferent arterioles to constrict

decrease in GFR and blood volume and blood pressure returns  to normal

 o Hormonal Regulation

 Angiotensin II- constricts afferent and efferent arterioles,  

diminishing GFR

 Artial Natriuretic Peptide (ANP)- relaxes mesanglial cells,  

increasing capillary surface area and GFR

Step 2: Tubular Reabsorption (Filtrate to Blood) 

∙ Tubular reabsorption begins when the filtrate enters the proximal tubules ∙ Reabsorbed substances follow either the transcellular route or  paracellular route 

o Transcellular Route: Substances move from the apical membrane  cytosol  basolateral membrane of tubules endothelium of  

pertitubular capillaries  

o Paracellular Route: Movement of substances between the tubule  cells via tight junctions

∙ Almost all nutrients are reabsorbed: water, glucose, amino acids, ions o Glucose, amino acids (nearly 100%), bicarbonate,water,  

sodium,chloride, potassium, magnesium,phosphate, urea (50%) ∙ The reabsorption process is either active or passive ( diffusion, facilitated  diff, osmosis)  

o Primary Active Transport: ATP is used via pumps (Sodium/potassium  pumps)

o Secondary Active Transport:  

 Controlled by ion’s electrochemical gradient

 Symporters move substances in the same direction; Antiporters  move substances in opposite directions

 Glucose, amino acids, ions, and vitamins are reabsorbed by  secondary active transport

∙ Water Reabsorption:

o Obligatory Water Reabsorption: water follows solutes that are  reabsorbed

o Facultative water reabsorption: water absorption that is regulated by  ADH

∙ Reabsorption in the Proximal Convoluted Tubule

o Glucose and amino acids are reabsorbed completely here; 65% of Na+  and water  

o Almost all of uric acid and ½ of urea are reabsorbed; both are secreted  into the filtrate later

∙ Reabsorption in the Nephron Loop

o Water is able to leave the descending limb but not the ascending  because of the scarcity of aquaporins in the tubule

o No solute reabsorption in the descending limb; occurs in the ascending limb both actively and passively  

o In the thin ascending limb, Na+ move down its concentration gradient  created by the water reabsorption

o In the thick ascending limb, Na+--K+--2CL- symporter helps Na+ get to the surface. Sodium potassium pump creates an ionic gradient to push  the symporter. Also contains Na+--H+ antiporters.

∙ Reabsorption in Distal Convoluted Tubule and Collecting Duct o Hormones help fine-tune reabsorption in the DCT and collecting duct o Antidiuretic hormone (ADH):

 Inhibits urine output and urea reabsorption

 Amount of ADH regulates the number of aquaporins which  

regulates water

o Aldosterone:

 Helps with the remaining reabsorption of Na+

 Increase blood volume and pressure by enhancing Na+  


 Reduces blood K+ concentrations

o Atrial natriuretic peptide (ANP)  

 Reduces blood Na+ therefore decrease blood volume and  


 Lowers Na+ content via direct inhibition of Na+ reabsorption at  the collecting ducts

o Parathyroid hormone (PTH)

 Increases reabsorption of Ca2+

Step 3: Tubular Secretion (Blood to Filtrate) 

∙ This process moves substances from pertiubular capillaries through tubule  cells into the filtrate

o H+, K+, NH4+, creatinine, and some organic acids/bases

∙ Urine contains filtered and secreted substances

∙ Important for ridding the body of foreign and toxic substances (drugs),  ridding the body of excess K+ (potassium ions), and controlling blood pH


∙ Formation of Dilute and Concentrated Urine

∙ Mechanisms for Medullary Osmotic Gradient

Urine Transportation and Storage

∙ Micturition, or urination is the process that allows for the emptying of the  urinary bladder

o The accumulation of urine in the urinary bladder causing it to distend  which activates stretch receptors

o Detrusor contractsinternal urethral sphincter opensurine is expelled Chapter 26: Electrolytes 

26.1: Body Fluid Compartments

∙ Two main fluid compartments

o Intracellular fluid (ICF) compartment

 About 2/3 of body fluid

 Consist of trillions of tiny individual compartments

o Extracellular (ECF) compartment

 1/3 of our body’s fluid that is outside cells

 A body’s internal environment and a cell’s external environment  2 Subcompartments

∙ Plamsa- fluid portion of blood

∙ Interstitial fluid (IF)- fluid found in between the spaces of  

tissue cells

Electrolytes and Nonelectrolytes  

∙ Solutes are classified as either nonelectrolytes or electrolytes ∙ Electrolytes: chemical substances (salts, acids, bases) that dissoiciate into  ions in water; ions can conduct an electrical current

o Milliequivalents per liter (mEq/L): measure of electrical charges per  liter of solution

∙ Nonelectrolytes: cannot dissociates ions due to their covalent bonds; organic  molecules (glucose,lipids, creatinine, urea)


∙ Both have a chief cation that is sodium; chief anion is chloride ∙ ICF:

o Contains small amounts of Na+ and Cl

o Major cation: Potassium Major anion: HPO42-

∙ ECF:

o Smalll amounts of Cl

o Major cation: Na+ ; Major anion: Cl

Fluid Movement among Compartments

∙ Osmotic and hydrostatic pressure control the regulation of continuous  exchange and mixing of body fluids

26.4: Acid-Base Balance

∙ Due to the abundant hydrogen bonds proteins have, the proteins are  influenced by H+ concentration

∙ Normal pH of arterial blood is 7.4

∙ Alkalosis or alkalemia is when the pH of blood rises over 7.45 ∙ A drop in arterial blood that is below 7.35 results in acidosis or academia ∙ Most hydrogen ions come from metabolic by-products or end products ∙ Regulation of H+ concentration in the blood: 

o Chemical buffers- first line of defense; resist pH changes

o Brain stem respiratory centers- respiratory rate and depth changes to  compensate for acidosis or alkalosis 

o Renal mechanisms- kidneys are a major factor in acid-base regulation;  take hours to days to alter blood pH 

∙ Respiratory system and Renal system are the physiological buffering  systems; work together to control pH by regulating the amount of acid or  base in the body 

∙ 3 Major Chemical Buffer Systems 

o Bicarbonate Buffer System, Phosphate Buffer System, Protein Buffer  System 

∙ Respiratory Regulation of H+ 

o Respiratory system responsible for eliminate CO2

o CO2+ H20  H2CO3 (carbonic acid) H+ + HCO3- (bicarbonate ion)  Carbon dioxide unloading: reactions moves to the left, and  hydrogen ions are made from carbonic acid which is  

reincorporated into water 

 Carbon dioxide loading: reaction moves to the right and  

hydrogen ions are buffered by proteins 

o Respiratory acidosis or respiratory alkalosis develops when there is a  pH imbalance due to respiratory system problems  

 Respiratory acidosis- hypoventilation; accumulation of CO2 in  the blood, increased H+ concentration in blood; blood becomes  acidotic; mainly caused by bradypneia  

∙ Renal Compensation: Kidneys will release HCO3-  

(bicarbonate) to increase pH level 

 Respiratory alkalosis- hyperventi lation; increased elimination of CO2 out of the body; H+ concentration decreases; blood  

becomes alkalotic  

∙ Renal Compensation: Kidneys will excrete, or urinate  

bicarbonate to lower pH levels 

 Metabolic acidosis- too much acid builtup in the body fluids;  bicarbonate levels are dropped; blood pH is acidic (<7) 

∙ Causes- diabetic ketoacidos, diarrhea (excessive loss  of HCO3-), renal failure

∙ Respiratory Compensation- hyperventilation to expel  

CO2 to increase blood pH and increase bicarbonate  

levels: deep, rapid breathing

 Metabolic alkalosis: excessive loss H+ ions (acids);  increased HCO3 (bicarbonate) levels; or body 

∙ Causes: Vomitting;hypoaldosteronismcauses renal  

tubules to keep Na+ and lose hydrogen ions and  

potassium ions 

∙ Respiratory Compensation: hypoventilation to keep CO2 levels high so that bicarbonate levels will  

come back down to normal; slow, shallow breathing

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