Notes from February 24 - March 9
Notes from February 24 - March 9 BIO 1144
Popular in Biology II
Popular in Biology
This 10 page Class Notes was uploaded by Grey Garris on Sunday March 13, 2016. The Class Notes belongs to BIO 1144 at Mississippi State University taught by Dr. Williamson in Spring 2016. Since its upload, it has received 56 views. For similar materials see Biology II in Biology at Mississippi State University.
Reviews for Notes from February 24 - March 9
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/13/16
Garris 1 BIO 1144 Bio II with Dr. Williamson Animal Bodies and Homeostasis ● Cells →Tissues →Organs → Organ System ○ Tissues are a group of similar cells that operate together for a common goal. Organs are a group of tissues that operate together for a common goal. Organ Systems are groups of organs that operate together for a common goal. ● Epithelial Tissues: Epithelium and Glands ○ Epithelium ■ Epithelial Tissue covers body surfaces and acts as the lining of body cavities. It is Avascular, which means that there is no direct blood supply to the tissue so molecules enter by diffusion through underlying connective tissues. Epithelial Cells are tightly packed together and have little Extracellular Matrix. There is a thin film of acellular, gellike material between the Epithelial Cells and the underlying connective tissue. This film is called the Basal Lamina or the Basement Membrane. It is secreted by the cells on both sides. ■ Organization ● Number of Cell Layers the number of cell layers between the basement membrane and the surface has a specified name. Simple means 1 layer and Stratified means 2 or more layers. ● Cell Shape ○ Squamous These cells are very thin and irregularly shaped. ○ Cuboidal These cells are equal in height and width when viewed from the side and have a spherical nucleus in their centers. ○ Columnar These cells are taller than they are wide and they have an oval shaped nucleus in the lower third of the cell. ● Epithelial Tissue Types ○ Simple Squamous A single layer of flat, irregularly shaped cells. They act as sites of exchange, chemical excretion and molecule absorption. ○ Simple Cuboidal A single layer of cells that are as wide as they are tall. They act as sites of molecule absorption, chemical excretion, and are protective. ○ Simple Columnar A single layer of cells that are taller than they are wide. They act as sites of chemical excretion, molecule absorption, and are protective. ○ Pseudostratified Columnar A single layer of Columnar cells but it looks like multiple layers because some of them are larger than others. Regardless, it is one layer because each cell is in contact with the basal membrane. ○ Stratified Squamous Multiple layers of flat, irregularly shaped cells. This kind of tissue acts as protection. In the case of skin cells in humans and many mammals, the layers grow upwards and as they do so they become filled with Keratin until they die. This Keratin allows them to resist water loss and protect the underlying cells and tissue from damage from UV Light and pathogens. ○ Stratified Cuboidal Multiple layers of cells that are as wide as they are tall. This has limited distribution throughout the body and acts as transportation. Garris 2 ○ Stratified Columnar Multiple layers of cells that are taller than they are wide. This has limited distribution in the body and functions as transportation. ○ Transitional Epithelial Tissue This type of tissue is only found in the urinary tract, specifically in the bladder. They have folds in their plasma membranes to accommodate stretching of the bladder as it expands with urine. ○ Glands ■ Glands are actually pocketlike structures that are derived from Epithelial Tissue. ■ Parts ● Parenchyma These are the secretory units and ducts. ● Stroma Connective tissue surrounding the above as protection and support. ■ Types ● Exocrine Exocrine glands have ducts that allow them to transport the products of the glands. ● Endocrine They lack ducts and are highly vascularized (have blood vessels surrounding them) and the hormones they secrete are carried through the blood. ● Connective Tissues ○ The primary functions of Connective Tissue are to: provide structural support to organs and other tissues as well as bind them together, act as a medium of exchange, act as defense and protection, and some function for fat storage. The cells that comprise these tissues are dispersed in Extracellular Matrix. ■ Extracellular Matrix A substance comprised of fibers, cells, and other secretions. ● Ground Substance A gellike material that functions to promote diffusion and resists compression and stretching. It is composed of Glycosaminoglycans (GAGS) and Proteoglycans. ○ GAGS These are polymers of disaccharides that are highly negatively charged and allow for attraction of water. ○ Proteoglycans These are cores of protein that the GAGS are directly attached to. They further the attraction of water. ● Fibers These are strands of protein that are secreted by the cells of the connective tissue. ○ Collagen These are the most common type. They have great tensile strength and provide structural support and prevent great stretching. ○ Elastic These allow for elasticity (stretching and then returning to the original form with little warping) and stabilize the matrix. ○ Reticular These are types of Collagen fibers that help provide the structural framework for the matrix. ● Cells There are multiple types of cells in the matrix that help it exist. ○ Fibroblasts These secrete the materials that make up the matrix. ○ Mast Cells These cells initiate inflammatory responses. ○ Macrophages They are Phagocytes (cells that consume materials actively) that remove debris from other cells in the matrix and prevent infection by consuming pathogens. ○ Leukocytes These prevent infection by consuming pathogens. ○ Plasma Cells These secrete antibodies, which prevent infection from pathogens that have previously entered the body. ■ Types of Connective Tissue ● Loose Also called Areolar, the collagen fibers within are randomly arranged. Garris 3 ● Dense The collagen fibers within the matrix are densely packed and arranged systematically. ● Adipose This is fat tissue and allows the body to have shape and contour. ● Cartilage This functions as a support tissue. ● Bone This functions as a support tissue as well. ● Blood This allows for transport of materials and protection from pathogens. ● Muscle Tissues ○ Muscle Tissue are specialized for contraction to allow the body mobility. ○ Types ■ Skeletal The contractive movement of this muscle is voluntary and each cell has multiple nuclei. It is also striated, which means that there is a regular pattern of proteins in the cells that allow the muscle to contract. This pattern shows up as a regular pattern of dark and light. Most of these muscles are associated with bones and body movement but some (like the muscles in the upper part of the throat) help move cartilage. ■ Cardiac The contractive movement of this muscle is involuntary and the cells are striated and have 1 or 2 nuclei. The cells also branch and connect to multiple others to form something similar to a net. This net of muscle allows for faster communication between the cells to sync the contractions, which is vital as regular heartbeats are necessary. Most cardiac muscle is associated with the myocardium of the heart. ■ Smooth The contractive movement of this muscle is involuntary, is striated, and the cells have only one nucleus. They surround the walls of hollow organs and glands. ● Nervous Tissue ○ Nervous Tissue is comprised of Neurons and Neuroglial Cells, which allow for the transmission of information. ○ Neurons ■ Neurons are the only cells in the body capable of conducting nerve impulses, which control the rest of the body functions. ● Dendrites Dendrites are short tendrils that branch out from the Cell Body. They conduct the nerve impulse into the Cell Body. ● Cell Body Called the Soma. It contains most of the cytoplasm as well as the main organelles. It conducts the signal that the Dendrites drew inwards and sends it down the axon. ● Axon The Cell Body has a single, long tendril at the end opposite the Dendrites. This tendril is called the Axon. It conducts the nerve impulse out of the Neuron and towards the Dendrites of other Neurons as it branches at its ends. ○ Neuroglial Cells These are cells that surround the Neurons and work as protection and support as well as helping the nerve impulse move along the chain. They do NOT conduct the impulses though. ● Homeostasis ○ Homeostasis is the process of the body adjusting to changes in external stimuli in order to maintain a stable internal environment. It just means the body is trying to say the same as it always is. ■ Set Point The normal value for the variable under distress. ■ Sensor The sensors for the variable monitor its variations and signal the Integrator. ■ Integrator The Integrator reads the signals from the Sensors and compares them to the Set Point to determine whether or not to signal the Effector. ■ Effector The Effector is a mechanism that acts to establish the Set Point of the variable again. ○ Feedback Systems Homeostasis operates under the fundamental feature of Feedback Systems, which are systems of responding to changes in both the internal and external environments. ■ Negative Feedback The most common. Garris 4 ● They prevent small deviations from the Set Point from becoming too large. ● It determines the degree of the variation and responds accordingly to reverse the change. It also prevents the Effector from overcompensating and making the issue worse but in the other direction. ● Example: Thyroxine concentration in the blood. The Hypothalamus signals the Anterior Pituitary to signal the Thyroid to produce Thyroxine. The Thyroxine produced then acts as a signal to the Hypothalamus and Anterior Pituitary to STOP sending signals out so that excess Thyroxine is not forced into the system by the Thyroid. ■ Positive Feedback This are very, very rare in biological systems. ● They amplify deviation from the Set Point. ● Example: Oxytocin acts as the chemical signal to induce labor in mammals. Oxytocin triggers the contractions that begin labor and those contractions of the muscle produce more Oxytocin, which increases the contractions, which causes more Oxytocin to be produced and so on. ■ Feedforward Regulation ● This response is pre emptive/anticipatory. The body prepares for a deviation from the Set Point before it happens. Many of these responses result from learning. ● Example: In athletic competitions, athletes’ heart rates and breathing rates increase before they even start the competition because the body anticipates what is about to happen and prepares for it by flooding the body with adrenaline. Digestive Systems ● Organisms ingest organic macromolecules for two general purposes: the generation of energy in the form of ATP and the “creation” of smaller, more usable molecules using the macromolecules. ● Functions ○ Ingestion ○ Digestion The mechanical and chemical breakdown of food. Mechanical breakdown is physically crushing and dividing the food via teeth, stomach muscle contractions, etc. Chemical breakdown is the chemical alteration of the materials via chemical reactions with enzymes. ○ Absorption Digested food is absorbed by the Epithelial Cells lining the GI Tract. ○ Transport Food is moved from organ to organ to allow for continued absorption and processing of the materials. ○ Elimination Undigested or unabsorbed food is removed in the feces. ● Feeding Mechanisms Different ways of eating. ○ Suspension Feeding (Filter Feeders) They filter organic molecules from the wall with cilialined tracts (like in bivalve mollusks and sea squirts) or filterlike “organs” such as the baleen of baleen whales. ○ Bulk Feeders They eat food in large chunks. ■ Carnivores They consume meat by preying on animals. These are predators and scavengers. They have sharp, angular teeth designed for ripping and tearing. They have large Canines. ■ Herbivores They consume plant matter. These are grazers. They have large, ridged, wide surfacearea teeth suited for grinding and crushing plant matter. They have molars. ■ Omnivores They consume both plants and animals. They have both ripping and tearing Canines and grinding Molars and Premolars. ○ Fluid Feeders They consume fluid food. They do not need teeth in most cases but some developed them to puncture living prey to consume the body juices of the animal. ● Mechanisms of Digestion and Absorption ○ Intracellular Digestion Garris 5 ■ This is mainly present in sponges because food enters the cells directly via phagocytosis. ■ This process cannot meet the metabolic demands of large, active animals for very long and they have no ability to store food. ○ Extracellular Digestion ■ Food is primarily digested outside of the cells. This protects the interior of the cells from the hydrolytic enzymes that would destroy or harm them. This allows the organism to consume large amounts of food, which enters the digestive cavity to be stored, slowly digested, and gradually absorbed by the cells of the body. ■ Gastrovascular Cavity ● Simplest form of Extracellular Digestion. A single opening serves as both the entry for food and the exit for waste. Food is partially digested in the cavity and then the dissolved particles are absorbed by Phagocytosis. ■ Alimentary Canal GI Tract ● A single, elongated tube with an entry end for food and an exit end for waste. It is lined by Epithelial Cells that synthesize the digestive enzymes, secrete hormones, and transport and absorb digested food. ● The walls of the Canal contain smooth muscle to operate the mechanical breakdown actions. ● There are several specialized regions of the Canal. Eac has a different environment and serves a different purpose. ● Vertebrate Digestive Systems ○ Vertebrates have an Alimentary Canal as well as accessory structures such as teeth, a tongue, salivary glands, etc. ○ Parts ■ Oral Cavity ● Teeth Begin the mechanical breakdown of the food by tearing/grinding the food. Incisors (thin front teeth) act to bite off food, Canines (sharp angular teeth) act to tear and shred food, and Molars and Premolars (every other tooth) act to grind the food down. ● Salivary Glands They produce saliva to moisten food. The saliva also has antimicrobial agents and has Salivary Amylase, which is an enzyme that begins the chemical digestion of carbohydrates. ● Tongue It has Lingual Papillae, which are basically ridges that help to grip food and also contain taste buds. It aids in swallowing, especially by helping to create the bolus (the wet ball of food and saliva that gets swallowed). ■ Pharynx The area generally referred to as the throat. ● Tonsils They are lymphoid tissue (immune system) that are found surrounding the port of entry into the body cavity. The lymphocytes within provide protection from pathogens. ■ Esophagus The tube conducting the food to the stomach. ● Peristalsis The actual movement of the muscles surrounding the esophagus that acts in a wavelike motion to force food down into the stomach. It is involuntary. ● Crop Some organisms have it, some don’t. It is a storage organ and is just a dilated area before the stomach that acts as a storage space for food. Little to no digestion occurs here. ■ Stomach The large, most dilated part of the Canal. ● Muscle contractions force the food to break apart via mechanical breakdown and the stomach regulates the rate of emptying of the Chyme into the Small Intestine. Garris 6 There is no lipid or carbohydrate digestion here. Chyme is the liquified, acidic slurry of food and enzyme created in the stomach. Nasty. ● Glands ○ Parietal Cells They secrete the Hydrochloric Acid in the stomach that allows for chemical breakdown of food. and killing of microbes and other pathogens. ○ Chief Cells They secrete Pepsinogen, which, once it interacts with Hydrochloric Acid, becomes Pepsin. Pepsin is a general dissolver of proteins. They secrete Pepsinogen instead because if they created the Pepsin within themselves the Pepsin would destroy the proteins within the Chief Cells themselves. ● Herbivores They have to digest the cellulose in the plants they eat but lack cellulase. Therefore, they have microbes in their Canal that consume the cellulose and produce the needed monosaccharides. ○ Simple Stomach In nonruminant herbivores (meaning they don’t throw their food up to chew and swallow it again) such as rabbits, horses, and rats. The first region of the large intestine is called the Cecum and has the cellulose digesting microbes. ○ Complex Stomach ■ Forestomach is comprised of three parts prior to the True Stomach. ● Rumen Cellulose digesting microbes. ● Reticulum Cellulose digesting microbes. ● Omasum Absorbs water and salt from food. ■ Abomasum True Stomach. Contains acids and Proteolytic Enzymes. ■ Intestines ● Small Intestine Long tube that the stomach empties the Chyme into. It finishes the digestion of Proteins and Carbohydrates into Amino Acids and Monosaccharides, respectively. It also begins and ends the digestion of lipids and Nucleic Acids into Glycerol & Fatty Acids and Nucleotides, respectively.The length of the SI varies but is generally longer in herbivores because they need more time to digest the plant materials. ○ Surface Modifications The surface area of the small intestine is greatly increased to provide for more absorption. ■ Plicae Circulares There are folds in the wall that project into the lumen (the space). ■ Villi The individual bumps are called Villi and increase the surface area. ■ Microvilli The cells comprising the outer wall of the Villi have highly folded regions of their plasma membranes as well. ● Large Intestine It’s primary function is to store and concentrate feces and absorb remaining salt and water. Bacteria within it feed on remaining food and produce vitamins, which is a positive. It includes the Cecum in some cases and also includes the Colon, Rectum, and Anal Canal. ○ Accessory Digestive Glands ■ Pancreas It produces extra digestive enzymes and also adds the chemical Bicarbonate, which acts as a buffer so the pH of the intestine does not become too acidic. Garris 7 ■ Liver The Liver produces bile for the emulsification (just remember the word and think of it as making things easier to digest) of lipids (fats). ■ Gall Bladder It stores and concentrates the bile created by the Liver. Nervous System ● The Nervous System is comprised of all Neurons and the many types of cells that protect them, which are called Neuroglial Cells. It is divided into the Central Nervous System (CNS), which is comprised of the brain and spinal column and the Peripheral Nervous System (PNS), which is comprised of everything else. In the Peripheral Nervous System a Nerve is a group of axons that are bound together and a Ganglion is a group of somas (cell bodies). ● Neuroglia ○ These are the supportive cells. They do NOT conduct OR generate an action potential or graded potential. They simply protect, feed, and aid the Neurons. ○ Astrocytes ONLY in thCNS . They form what is called the bloodbrain barrier. To get material to neurons there are many capillaries that go through the brain tissue. These capillaries are not directly next to Neurons, instead they are surrounded by Astrocytes, which absorb the material from the blood and then transfer it to the Neuron. They protect the Neurons from damaging materials such as alcohol. This trait makes them the metabolic support system for CNS Neurons. ○ Microglia ONLY in thCNS. These are tiny, freemoving cells that are phagocytes. This means that they just kind of run around the brain eating up waste material, dead cells, and pathogens. ○ Ependyma ONLY in the CNS. These line the central canal (the hollow area that the spinal cord is held in) of the Spinal Column and the ventricles of the brain (there are “hollow” areas in the brain called ventricles. These cells are ciliated and produce the CerebrospinalFluid, which is the liquid in which the brain and spinal cord are suspended. ○ Oligodendrocytes ONLY in th CNS. These form the Myelin Sheath. Myelin is not so much a material as a name for the protective coat around a Neuron’s axon. Oligodendrocytes are cells in the space between Neurons that project parts of their cell membranes outwards. These projections wrap around the axons to form the Sheath. They form many of these projections, sometimes attaching to multiple Neurons, to the point that they look like spiky balls stuck to the axons. ○ Schwann Cells ONLY in PNS. These form the Myelin Sheath in tPNS . These are single cells that wrap their entire bodies around part of the axon. They are small so there are a lot of these wrapped around a single axon. There are spaces between the Cells. ● Neurons ○ Neurons are the structural/functional unit of the Nervous System. They send and receive signals to various parts of the body and are present in all animals except sponges. ○ Parts ■ The cell body of a Neuron is called the Soma, which contains the nucleus and most of the organelles of the Neuron. Groups of Soma in the CNS are called Nuclei while groups of Soma in the PNS are called Ganglia. ■ Dendrites are multiple, short branches at one end of the Soma that generate a Graded Potential when excited by another Neuron’s Action Potential from its Axon. ■ The Axon is the long, singular projection at the end of the Neuron opposite the Dendrites. It generates the Action Potential and the first segment of the Axon is called the Axon Hillock. ○ Types of Neurons ■ Sensory Neurons Also called Afferent Neurons. They send information from the PNS to the CNS. ■ Interneurons These Neurons transmit signals to other neurons. Garris 8 ■ Motor Neurons Also called Efferent Neurons. They send information from the CNS to the PNS. ■ Nerves in the PNS ● Sensory Clusters of Sensory Neuron Axons. ● Motor Clusters of Motor Neuron Axons. ● Mixed Clusters of Axons from both types of Neurons. ● Electrical Properties of Neurons and Signal Conduction ○ The Plasma Membrane of a Neuron is the barrier that separates charged particles on either side. The concentration of these ions is different inside and outside the cell and this difference is what generates an Electrical Force (in volts) and when the cell is like this it is Electrically Polarized. The number that defines the difference across the Plasma Membrane is called the Membrane Potential. ○ Resting Membrane Potential ■ This is the Membrane Potential of the Plasma Membrane when the Neuron is at rest. The Neuron is at rest at any time that it is not conducting an Action Potential. The charge within the Neuron is normally 70 milliVolts. The negative charge is mainly due to the presence of proteins, which have many negative charges, within the cell. ■ This Potential is established because of the Ion Concentration Gradient, which is that difference in ion concentration discussed above. The two big ions that control this gradient are Sodium (Na) and Potassium (K). + + ● The Na /K ATPase Pump (think of that as one word) is a protein pump in the Plasma Membrane that constantly moves 3 Na out of the cell and 2 in. This forces more positive charge to the outside of the cell and establishes the gradient. ● Ungated Na + and Ungated K Channels These are protein channels that allow for fast, passive movement into and out of the cell for their respective ions. Because there is a higher concentration of outside the cell and a higher + + concentration of K inside, the Na rushes in and th rushes out when the Neuron is at rest. There are 10100 times more Channels than Na Channels + so K is considered more valuable to the cell. ○ Neuron Communication ■ Neurons “communicate” by rapid changes in the MP. The direction of ion movement across the Plasma Membrane depends on the Electrochemical Gradient (ECG), which determines the MP. This is established by two different types of ion channels in the Plasma Membrane: Voltage Gated, which open/close in response to the MP, and Ligand Gated, which open/close when Ligands (binding molecules such as neurotransmitters) bind to the receptors. These channels allow for the transference of even mor and K. ● Depolarization The Neuron becomes less polarized because the GP from the Dendrites opens the Voltage Gated Channels and Na+ rushes in. It’s called Depolarization because, since the Resting Membrane Potential is negative, the positive ion influx forces it positive for a moment. ● Hyperpolarization The Neuron, to adjust for the change it was forced to undergo, forces a lot of those positive ions out and briefly goes even more negative than the Resting Membrane Potential, which is why it’s Hyperpolarization. ■ Signal Transduction ● Graded Potentials These are changes in the MP of the Dendrites that are triggered by an Action Potential from the axon of another Neuron. They spread a short distance before dying out but if a GP is strong enough, or if enough of them are generated at one time, then the Potential moves through to the Neuron. Garris 9 ● Action Potentials These are long distance electrical signals that include a large depolarization. They actually reverse the MP for a brief time. They begin at the Axon Hillock and travel down the Axon. These are all or none events in that if the Graded Potentials are not strong enough, an AP won’t be generated at all, but if they are then one will be. The AP is actively regenerated all down the axon. They initiate the GP at the Dendrites of the next cells. APs goes in ONE DIRECTION. They go from Axon Hillock to Axon Terminal, never the other way. ○ Generation ■ Depolarization The GPs from the Dendrites travel to the Axon Hillock. If the signal is strong enough (able to force the inside of the cell to go up to 50mV instead of 70mV) then an AP is generated. This causes the Voltage Gated Na+ Channels to open, which allows quick Na+ influx, forcing the inside of the cell to temporarily become positively charge (referred to as temporary reversal of MP). ■ Repolarization Once the inside of the cell is positive the Inactivation Gate for the Voltage Gated Na+ Channel closes the Channel. Then the Voltage Gated K+ Channels open about a millisecond later and allow the K+ within the cell to flood out to put the cell back at RMP. As the K+ rushes out th+ +ll briefly becomes more negative than 70mV so the Na /K ATPase Pump works to establish the RMP again. ■ Absolute Refractory Period This is a very short time period where the Voltage Gated Na+ Channels are inactive and completely incapable of opening. This nonresponsiveness is key so that the axon does not accidentally send the AP backwards and it also limits the rate of the AP generation. ○ Factors Affecting Conduction ■ The larger the diameter of an Axon, the faster the conduction will be. ■ Myelination Myelinated Axons are significantly faster at conducting signals. The gaps between the cells that make the Myelin Sheath (Oligodendrocytes in the CNS and Schwann Cells in the PNS) are called the Nodes of Ranvier and allow for Saltatory Conduction, which is conduction that seems to allow jumping of the AP from Node to Node. ■ Synapses ● The junction between the axon of one neuron and the dendrites of another, the junction between a muscle cell and axon, or the junction between a gland and an axon. They can be Electrical or Chemical. Most are chemical, though some allow the electrical charge to jump between the Axon and Dendrites. ○ Chemical Synapses ■ They use Neurotransmitters, which are either Inhibitory or Excitatory Molecules released into the synapse by the Axon Terminals. There are more than 100 in animals, including: GABA, which is the most common inhibitor, Glutamate, which is the most common excitatory neurotransmitter, and Acetylcholine, which is excitatory in skeletal muscles and the brain but inhibitory in cardiac muscle. ■ Signal Transmission Process Garris 10 ● The Presynaptic Neuron’s Axon Terminals contain vesicles (balls of cell membrane) that float in their cytoplasm that hold the Neurotransmitters. When Calcium is allowed the permeate the Cell Membrane it binds to the vesicles and forces them to meld with the Cell Membrane and release the Neurotransmitters they contain into the Synaptic Cleft, which is the space between the Axon Terminal and Dendrites. The Neurotransmitter binds to the Dendrites of the Postsynaptic Neuron and either opens the Dendrite’s Channels (Excitatory) or closes them (Inhibitory). The Neurotransmitters that are not used up by this process are reabsorbed by the Presynaptic Neuron in the Reuptake Process. Then this happens again and again and again.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'