Biology 2 Exam 2 Study Guide
Biology 2 Exam 2 Study Guide BIOL 1040
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This 12 page Study Guide was uploaded by Courtney Luber on Thursday February 25, 2016. The Study Guide belongs to BIOL 1040 at Clemson University taught by Dr. William Surver in Fall 2016. Since its upload, it has received 141 views. For similar materials see General Biology II in Biology at Clemson University.
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Date Created: 02/25/16
Biology 1040 Exam 2 Study Guide Chapter 38: Musculoskeletal System Muscle Tissue—most abundant tissue in animals o Smooth—not striated; involuntary o Skeletal—striated; voluntary o Cardiac—striated; involuntary Muscles & bones interact to produce movement o Antagonistic Muscles are connected to bones by tendons o Can only contract requiring an antagonistimuscle to Reverse the action Relengthen muscles Muscle fiber = muscle cell Skeletal muscle o Multinucleated o Striated Sarcomere—the functional unit of skeletal muscle what contracts and relaxes and allows the muscle to function o Unit of contraction in skeletal muscle o Z bands = dark bands on end of sarcomere Actin—thin fibers; attached to z lines Myosin—thick fibers; between actin; not attached to anything Muscle cell shortens because the sarcomere within it is shortening Know anatomy of sarcomere & how it functions Skeletal Muscle Contraction o Sliding filament model—a sarcomere contracts (shortens) when its thin filaments slide across thick filaments; mechanism by which the sarcomere shortens Contraction shortens the sarcomere without changing the lengths of the thick and thin filaments Actin slides across myosin—myosin stays put; myosin reaches and grabs hold of actin When a muscle is fully contracted, the thin filaments overlap in the middle of the sarcomere I band = area near z-line H zone = all myosin; disappears when sarcomere contracts o Myosin heads of the thick filaments Bind to ATP and Extend to high energy states o Myosin heads then Attach to binding sites on the actin molecules Pull the thin filaments toward the center of the sarcomere o A motor neuron Carries an action potential to a muscle cell Releases the neurotransmitter acetylcholine from its synaptic terminal and initiates a muscle contraction An action potential in a muscle cell passes along the T tubules and into the center of the muscle fiber o Calcium ions Without calcium being released, a muscle would never contract Calcium releases myosin-binding sites Are released from the ER Bind to the regulatory protein tropin resulting in the movement of tropomyosin away from the myosin-binding sites and allowing contraction to occur o When motor neurons stop sending action potentials to the muscle fibers The ER pumps Ca++ back into the cytosol Binding sites on the actin molecules are again blocked The sarcomeres stop contracting The muscle relaxes o Neuromuscular junction—where neuron and muscle connect Chapter 39: The Respiratory System Mechanisms of Gas Exchange o Called respiration but not to be confused with cellular respiration o In humans and other animals with lungs, three phases Breathing Transport of oxygen and carbon dioxide Exchange of gases with body tissues o Respiratory surfaces must be Moist for diffusion Thin to facilitate diffusion o Blue blood vessel—high in carbon dioxide o Red blood vessel—high in oxygen o Most animals have specialized body parts that promote gas exchange Gills – present in most aquatic animals Highly vascularized Capillaries—smallest type of blood vessels Tracheal systems – insects Series of tubes that goes through the insect Lungs – terrestrial vertebrates o Gas exchange in fish is enhanced by Ventilation – by pumping water across their gills Countercurrent flow of water and blood – flow of blood is in the opposite direction of the flow of water Blood flow moves right to left in capillary Low in oxygenhigh in oxygen Water flow moves left to right High in oxygenlow in oxygen o The tracheal system of insects provides direct exchange between the air and body cells Spherical—opening into the tracheal system Every cell in an insect’s body is associated with a part of the tracheal system o Tracheal systems use tiny branching tubes that Reduce water loss Deliver air directly to cells o The circulatory system of insects is not involved in transporting gases o For a small insect, diffusion through the tracheae brings in enough O2 to support cellular respiration o Larger insects may ventilate the tracheal systems with rhythmic body movements that compress and expand the air tubes like bellows o In many insects, alternating contraction and relaxation of the flight muscles rapidly pumps air through the tracheal system o No capillaries in the tracheal system Human Respiratory System o Lungs—in-pocketing o Gills—out-pocketing o Diaphragm – separates thoracic and abdominal cavity o Air is inhaled through nostrils Filter Warmed and humidified Odors o Alveoli are well adapted for gas exchange with high surface area of capillaries o In alveoli O2 diffuses into the blood CO2 diffuses out of the blood o Close association between our respiratory system and our circulatory system (same in amphibians, not in insects) o Trachea—serves as a passageway into lungs; ring of capillaries o Know diagram of human respiratory system o Breathing Inhalation—movement of air into body Exhalation—movement of air out of body o Inhalation – negative pressure breathing Rib cage expands Diaphragm moves downward Creates an opening/space Pressure in lungs decreases Air drawn into the respiratory tract o Exhalation Rib cage contracts Diaphragm moves upward Pressure around lungs increases Air is forced out of respiratory tract o Not all the air is forced out – dead air Gas Exchange Systems o Breathing centers in the brain respond to CO lev2ls o A drop in blood pH increases the rate and depth of breathing Transport of Gasses in Humans o The heart pumps blood to two regions The right side pumps oxygen-poor blood to the lungs The left side pumps oxygen-rich blood to the body o In the lungs, blood gains O2 and loses CO2 o In the body tissues, blood loses O2 and gains CO2 o Respiratory pigments Blue, copper containing – mollusks and arthropods Red, iron containing, hemoglobin – most vertebrates and many invertebrates o Hemoglobin transports oxygen, buffers blood and transports carbon dioxide Hemoglobin in quaternary structure of a protein o Carbon dioxide transport Enters red blood cells Some transported by hemoglobin Rest reacts with water o Incre ase of hydrogen ion concentration lowers pH Chapter 40: The Circulatory System Introduction o Cells must Receive nutrients Exchange gases Remove wastes o Large and complex animals cannot rely on diffusion to do these o One function of the circulatory system is to facilitate these exchanges o Open circulatory system – arthropods and many mollusks A tubular heart—moves material in circulatory system Open-ended vessels—release contents into cavities Blood that directly bathes the cells and functions as the interstitial fluid o Closed circulatory system Vertebrates, earthworms, squids, octopuses A heart Vessels that confine blood, keeping it distinct from the interstitial fluid Capillaries—one cell layer in thickness o Cardiovascular system of vertebrates and consists of arteries, veins, capillaries Two-chambered heart o Atrium receives blood from veins o Ventricle pumps blood to gills via arteries o Arteries branch into arterioles that give rise to capillaries that collect back into venules which converge into larger veins o Only needs two chambers because it has a single circulatory system One chamber to receive; one chamber to pump blood back out o Blood passes through the heart of a fish once in each circuit through the body. o A single circuit would not supply enough pressure to move blood through the capillaries of the lungs and then to the body capillaries of a terrestrial vertebrate Land Vertebrates o Land vertebrates have double circulation Pulmonary circuit-- Systemic circuit—heartbodyheart o All land animals have the same two systems but have different kinds of hearts Three-chambered heart o Found in amphibians, turtles, snakes, lizards o Consists of 2 atria—receives blood from systemic system 1 ventricle—pumps blood to the pulmonary system o Separates oxygen-poor blood from oxygen-rich blood o i.e. Frogs can exchange gases through the skin; needs nucleus in RBC’s because it doesn’t have a transport system o Red blood cells don’t have a nucleus so there is more room for hemoglobin and therefore, more oxygen can be carried to the body Four-chambered heart o Found in crocodiles, birds, and mammals o Consists of 2 atria—not as thick as ventricles 2 ventricles—distinct separate chambers; pump blood to entire body Left ventricle is the thickest, most muscular chamber of the heart o These two circuits do not mix oxygen-rich and oxygen poor blood o Right versus left side Structure & Function of Blood o Blood consists of several types of cells suspended in a liquid called plasma which is about 90% water and contains many different kinds of substances o Plasma—liquid part of our blood o Two classes of cells are suspended in plasma o Red blood cells or erythrocytes transport oxygen bound to hemoglobin o White blood cells or leukocytes Function inside and outside the circulatory system Fight infections and cancer Monocytes and neutrophils are white blood cells which engulf and digest bacteria and debris from dead cells Platelets, cell fragments—involved in how our blood clots o All blood cells come from a common ancestor o Serum—blood minus clotting factor o Read evolution connection in textbook—link on powerpoint Mammalian Circulation o Artery—any vessel going away from the heart o Pulmonary artery—low in O , rich in CO 2 2 Control of Human Heart Beat o Cardiac cycle – The repeated contraction and relaxation of pumping of blood; two phases o Diastole – blood flows from veins into heart chambers o Systole – blood flows from atria into ventricles o The SA (sinoatrial) node generates electrical signals in atria and sets the rate of heart contractions o The AV (atrioventricular) node relays these signals to the ventricles and causes ventricular contraction On an EKG, the R wave represents contraction of left ventricle while the S wave represents contraction of right ventricle Human Blood Vessels o Arteries and veins Arteries carry blood away from the heart Veins carry blood towards the heart o Compare and contrast o Capillaries Have thin walls—one cell layer in thickness Are narrow about as wide as a red blood cell Increase surface area for gas and fluid exchange with the interstitial fluid o Sickle cell anemia—RBC’s lose their flexibility & cannot squeeze between capillaries anymore; lose limbs because blood does not circulate o Veins have valves that open and close to prevent blood from flowing backwards o Arteries do not need valves because blood is pumping forward Know why animals need two-chambered hearts vs three-chambered hearts, etc. Chapter 41: Osmotic Regulation and Excretion Water/Salt Balance o Osmoregulation is the homeostatic control of the uptake and loss of water and solutes such as salt and other ions o Osmosis is the process utilized o REVIEW OSMOSIS; MEMBRANE TRANSPORT; SOLUTE CONCENTRATION; HYPERTONIC, HYPOTONIC, ISOTONIC o Hypertonic solution—concentration is greater outside cell than inside o Isotonic—concentration is the same inside & outside of cell o Hypotonic solution—concentration is greater inside cell than outside o Osmoconformers Have body fluids with a solute concentration equal to that of seawater Face no serious challenges in water balance Many marine animals o Osomoregulators Have body fluids whose solute concentrations differ from that of their environment Must actively regulate water movement Include: Many land animals Freshwater animals Marine vertebrates such as sharks o Saltwater fish – live in a hypertonic environment Have a water conservation problem Lose water by osmosis Drink seawater Use their gills and kidneys to excrete excess salt o Freshwater fish – live in a hypotonic environment Gain water by osmosis (mainly through gills) Lose salt by diffusion to the more dilute environment Take in salt through their gills and in food Excrete excess water in dilute urine o Land animals Face risk of dehydration Lose water by evaporation and waste disposal How can we reclaim water & substances we lose? Gain water by drinking and eating and cellular respiration Conserve water by reproductive adaptations, behavior adaptations, waterproof skin, and efficient kidneys o The urinary system Forms and excretes urine Regulates the amount of water and solutes in body fluids o In humans the kidneys are the main processing centers of the urinary system Highly associated with the circulatory system Pair of organs toward the back of the body o Our kidneys extract about 180 L of fluid called filtrate that consists of Water Urea A number of valuable solutes including glucose, amino acids, ions, and vitamins o Our kidneys refine the filtrate Concentrating the urea Recycling most of the water and useful solutes to the blood o In a typical day we excrete only about 1.5 L of urine, the refined filtrate containing wastes o Water conservation is one of the primary functions of the kidneys o During filtration the pressure of the blood forces water and other small molecules through a capillary wall in the start of the kidney tubule forming filtrate Materials are forced into the kidney o Urine the final product of filtration leaves each kidney through a duct called a ureter o Both ureters drain into the urinary bladder o During urination urine is expelled from the bladder through a tube called the urethra o Blood enters the nephron through the renal artery and flows into a bed of capillaries called the glomerulus o Nephron—the functional unit of the kidney. The glomerulus and convoluted tubules are located in the kidney cortex, while collecting ducts are located in the pyramids of the medulla Loop of Henle (ascending) reabsorbs Na and Cl from the filtrate into the interstitial fluid (descending) aquaporins allow water to pass from the filtrate into the interstitial fluid Distal—further away from something Proximal—closer to something o Glomerulus doesn’t select what gets into the nephrons; up to the kidneys o The filtrate forced into Bowman’s capsule flows into the nephron tubule where it is refined o Two processes refine the filtrate Reabsorption water and valuable solutes such as glucose, salt, and amino acids are reclaimed from the filtrate Secretion excess H+ and toxins are added to the filtrate o The Loop of Henle acts as a countercurrent multiplier that uses energy to create concentration gradients. The descending limb is water permeable. Water flows from the filtrate to the interstitial fluid, so osmolality inside the limb increases as it descends into the renal medulla. At the bottom, the osmolality is higher inside the loop than in the interstitial + fluid. Thus, as filtrate enters the ascending limb, Na and Cl ions exit through ion channels present in the cell membrane. Further up, Na is actively transported out of - the filtrate and Cl follows. Osmolarity is given in units of milliosmoles per liter (mOsm/L). o nephron filtration, secretion, reabsorption increasing concentration gradient towards bottom of nephron distal tubule—sodium chloride is actively transported out of the filtrate o Excretion urine is expelled o Nitrogenous waste a toxic by-product of metabolism o Nitrogenous wastes are toxic breakdown products of proteins and nucleic acids o Animals dispose of nitrogenous wastes indifferent ways o An animal disposes of metabolic wastes by converting them to chemicals that can be extracted through an opening in the body o The type of waste product produced and how the animal disposes of it depends on Adaptations Habitat o Ammonia—type of nitrogenous waste Too toxic to be stored in the body (most toxic waste) Highly soluble in water Easily disposed by aquatic animals o Urea Produced in the vertebrate liver by combining ammonia and carbon dioxide Less toxic than ammonia A soluble form of nitrogenous waste o Uric acid Excreted by some land animals (birds, insects, land snails and many reptiles Relatively nontoxic Water –insoluble Excreted as a semisolid paste thus conserving water More energy expensive to produce o Hormones regulate the urinary system Antidiuretic hormone (ADH) regulates the amount of water excreted by the kidneys by signaling nephrons to reabsorb water from the filtrate returning it to the blood and decreasing the amount of water excreted o Diuretics Inhibit the release of ADH Alcohol and caffeine
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