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Bio Test 2
Study for bio test 2
209
Biology
Undergraduate 2
04/14/2013

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Cards

Term
Pathogen
Definition
Cause disease
Term
Vector
Definition
Carries a pathogen
Term
Fomites
Definition
Non-living vectors
Term

Antigen

 

Definition

Stimulates an immune response/productino of antibodies.

(Most are proteins or polypeptides)

 

Term
Immune response
Definition
Elimination of non-self (pathogens) before symptoins occur, or shortly thereafter.
Term
Self
Definition
You, molecular recognition
Term
Characteristic of verebrates
Definition
Have adaptive immunity
Term
Innate immunity
Definition

Does not require pre-exposure to pathogen.

1: Barrier defense

2: Internal defense

Term
Epitope
Definition

Antigenic determinant site

(Binds to antigen-binding site)

Term
Antibody
Definition
Produced in response to antigen
Term
Virulence
Definition
How quickly makes host sick/how sick the host gets. (how nasty it is)
Term
Attenuation
Definition
Decrease in virulence. Attenuated strains give a stronger immune response.
Term
Innate immunity of vertebrates
Definition
Barrier Defenses and Cellular innate defenses
Term
Barrier defenses
Definition

Innate immunity.

Epithelial tissues block entry.

Mucous membranes line digestive, respiratory, urinary and reproductive tracts.

Lysozymes in tears, saliva and mucous.

Acidic environment in stomach.

Oil and seat glands give human skin low pH

Term
Cellular innate defenses
Definition

Phagocytic cells: Detect fungal or bacterial components using receptors. They engulf cells, trapping them in vacuoles that fill with lysosome. Lysosome produces gases that poisons the engulfed pathogens, or degrade the components of the pathogens with lysosomes and enzymes.

Neutrophils, Macrophages, Dendritic cells, Eosionphils, Toll-like receptors (TLR)

Term
Neutrophils
Definition

Phagocytic cell

Circulate in blood and are attracted by signals from infected tissues and engulf and destroy infecting pathogens.

Term
Macrophages
Definition

Phagocytic cell

Large phagocytic cells.

Term
Dendritic cells
Definition

Phagocytic cell

Populate tissues that contact the environment, such as skinn. They stimulate adaptive immunity against pathogens.

Term
Eosinophils
Definition

Phagocytic cell

Important in defending against multicellular invaders, such as parasites. They discharge destructive enzymes.

Under mucous membranes

Term
Toll-like receptors (TLR)
Definition

On phagocytic cell

Binds to fragments of molecules characteristic of pathogens.

Term
TLR4
Definition
Located on immune cell plasma, recognizes lipopolysaccharide, a molecule found on the surface of bacteria.
Term
Negative Feedback
Definition
A return to the norm reduces or turns off a response.
Term
Ectotherm
Definition
Gain most of their heat from external sources.
Term
Endotherm
Definition
Warmed mostly by heat generated by metabolism.
Term
Heterotherm
Definition
Homeothermic endotherms. Allow temperature to drop w/in +/- 2 standard deviations of set pt.
Term
Poikilotherm
Definition
Body temp. is based around Ambient temp. Ta.
Term
Homeotherm
Definition
Stay around set pt. regardless of habitat. Relatively constant body temp. (Mostly endotherms.)
Term
Ambient Temperature
Definition
Temperature of surroundings (Ta).
Term
Body Temperature
Definition
Temperature of body. (Tb).
Term
Physiologicial thermoregulation
Definition

Very energy-intensive. Last resort

 

Includes shivering thermogenesis, non-shivering thermogenesis, torpor, aestivation, and hibernation.

Term
Shivering thermogenesis
Definition

A type of physiological thermoregulation.

Rapid contraction of skeletal muscles to produce heat. 

Term
Non-shivering Thermogenesis
Definition

A type of physiological thermoregulation.

 

Uncoupling of ATP synthesis in Electron Transport Chain.

Term
Torpor
Definition

A physiological state of decreased metabolism. Adaptation that enables animals to save energy while avoiding difficult and dangerous conditions. 

 

  • Many small mammals and birds exhibit daily torpor that is adapted to feeding patterns.
Term
Aestivation
Definition
Lowering of metabolic rate to get through drought or heat.
Term
Hibernation
Definition
Long term torpor that is an adaptation to harsh winter and food scarcity.
Term
Behavioral Thermoregulatiion
Definition
The pulling in of extremeties to conserve heat.
Term
Anatomical thermoregulation
Definition
Structure of the organism in order to conserve heat.
Term
Morphological thermoregulation.
Definition
Overall shape for heat conservation.
Term
Lymphatic System
Definition
A network of tubules intermingled between b/t the capillaries of the cardiovascular system. Drains into large veins of the circulatory system at the base of the neck.
Term
Lymph
Definition
Fluid lost by the capillaries. Composition is the same as interstitial fluid.
Term
Lactael
Definition
Part of the vertebrate lymphatic system. Initial point of entry into the lymph for chylomicrons.
Term
Lymph vessels
Definition
Have valves that prevent backflow of fluid. Act like veins except for lymph. Skeletal muscle contractions play a role in moving the lymph.
Term
Lymph Nodes
Definition
Organs located along the lymph vessels. Filter lymph and contain cells that attack viruses and bacteria.
Term
Spleen
Definition
Contains phagocytic cells that consume old erythrocytes.
Term
Interferon
Definition
Unique to vertebrate immunity. Proteins that provide innate defense by interfering with viral infections. Virus-infected body cells secrete interferons, which induce nearby uninfected cells to produce substances that inhibit viral reproduction. They limit cell-to-cell spread of virsues. Some white blodo cells secrete diffeterent interferons that help activate macrophages
Term
Complement system
Definition

Involved in inflammation. 20-30 proteins, part of enzyme cascade, released in cytokines. Only circulate in the blood as zymogines.

Antibodies activate the complement system.

Term
Inflammatory response
Definition

Histamine that is stored in granules of mast cells, triggers nearby blood vessels to dilate and become more permeable. Macrophages and neutrophils discharge cytokines, signaling molecules that enhance an immune response and promote blood flow to the site of injury or infection. 

Redness and increased temperature is caused by an increase in local blood supply. Swelling is caused by leaking fluid into the neighboring tissues.

Term
Adaptive immunity
Definition

Pathogen-specific recognition.

The binding of an antigen receptor to an epitope initiates the activation of the lymphocytes. 

Secondary immune response, being able to combat antigens quicker after the first exposure, is only in adaptive immunity.

Based on two types of lymphocytes, types of white blood cells, T cells and B cells. Lymphocytes originate from the stem cells in the bone marrow. T cells mature in the thymus gland, B cells mature in the bone marrow.

Term
Antigen:
Definition
Any substance that elicits a response from a B cell or a T cell
Term
Antigen receptor
Definition
Receptor that binds to just one part of one molecule from a particular pathogen.
Term
Epitope
Definition
Small accessible portion of an antigen that binds to an antigen receptor
Term
B cell antigen receptor
Definition
Y-shaped molecule consisting of four polypeptide chains, two light chains and two heavy chains. The tips of the Y-shape have a variable region, the rest is constant.
Term
Antibody/immunoglobulin (Ig)
Definition

Have the same Y-shaped organization of B cell antigen receptors, but are secreted rather than membrane bound.

Antibodies actually help defend against pathogens.

Term
T cell antigen receptor
Definition
T cells consist of an ᶛ chain and a ᵝ chain. The variable region of the ᶛ and the ᵝ chains form a single antigen-binding site.
Term
B cells:
Definition
Bind to epitopes of intact antigens ciruclating in body fluids
Term
T Cells
Definition
T cells bind only to fragments of antigens that are displayed on the surface of host cells. The host protein displays the epitope on the major histocompatibility complex (MHC) moleucle.
Term
Antigen presentation
Definition
The display of the antigen fragment in the groove of the major histocompatibility complex (MHC) molecule
Term
Effector cells
Definition
Short-lived cells that take effect immediately against the antigen
Term
Memory cells
Definition
Long-lived cells that can give rise to effector cells if the same antigen is encountered later in the animal's life
Term
Clonal Selection
Definition
Proliferation of a lymphocyte in response to an antigen.
Term
Ig M
Definition
First class of soluble antibody produced
Term
Ig-E
Definition
Allergens: Ig-E antibodies are created in response to exposure to an allergen and bind to a mast cell. When allergens bind to Ig-E receptors, they cross link causing the mast cell to release histamine from granule
Term
Ig-G
Definition
Most abudant antibody in blood
Term
Ig-A
Definition
Functions in active immunity. Provides additional passive immunity to infants digestive tract while they develop. Is found in tears, mucus membranes, breast milk, sweat and oil.
Term
Ig-D
Definition
Membrane bound B cell antigen receptors.
Term
TNZ
Definition

Thermal Neutral Zone

Alteration of Ta. Mr stays the same.

Term
UCT
Definition

Upper Critical Temperature

Too hot

Term
LCT
Definition

Lower critical temperature.

Too cold

Term
MR
Definition

Metabolic Rate

Rate of metabolism. CC O2/Hour

Term
Biological Optimum
Definition
Body is at its optimum functionality
Term
Range of tolerance
Definition
Stress zone outside of biological optimum.
Term
Compartmentalization
Definition
Increased surface area of the small intestine
Term
Carabolism:
Definition
Breaks down triglycerides into monoglycerides and fatty acids.
Term
Anabolism
Definition
Monoglycerides and fatty acids are anabolized into triglycerides. Triglycerides are incorporated into water-soluble glovules called chylomicrons.
Term
Hydrolysis
Definition

Lipase breaks down triglycerides down to fatty acids and monoglycerides.

Term
Coenzymes
Definition
Vitamin B7, coenzyme in synthesis of fat, glycogen and amino acids
Term

Villi
Definition
Finger-like projections from the large folds in the small intestine
Term
Microvilli
Definition
Microscopic finger-like projections from the epithelial cells of the villi
Term
Osmoregulation
Definition
Process by which animals control solute concentrations and balance water gain and loss.
Term
Osmoregulators
Definition
Control internal osmolarity independent of that of its environment
Term
Osmoconformers
Definition
Isoosmotic with surroundings
Term
Euryhaline
Definition
Animals that can survive large fluctuations in external osmolarity. Euryhaline osmoconformers include many barnacles and mussels. Euryhaline osmoregulators are striped bass and various species of salmon.
Term
Stenohaline
Definition
Cannot tolerate substantial changes in external osmolarity
Term
Uricotelic
Definition
Organism that excretes uric acid.
Term
Ammonotelic
Definition
Organism that excrete ammonia
Term
Ureotelic
Definition
Organism that excrete urea.
Term
Uric acid
Definition
Produced by most reptiles, insects and land snails. It is relatively nontoxic and does not readily dissolve in water. It can be excreted as a semisolid past which reduces water loss. Uric acid requires lots of ATP to synthesize.
Term
Urea
Definition
Produced by mammals, most amphibians, sharks and some bony fishes. Produced in the vertebrate liver, also a product of metabolic cycle that combines ammonia with carbon dioxide. Very low toxicity, can transport urea in circulatory system and store it safely at high concentrations.
Term
Ammonia
Definition
Produced by most aquatic animals. Ammonia can only be tolerated at very low concentrations. Access of water is needed to keep ammonia dilute. Fish lose most of their ammonia as NH4 through gills.
Term
Concentration gradient
Definition
A region along which the density of a chemical substance increases or decreases.
Term
Filtration
Definition
The extraction fo water and small solutes, including metabolic waste from the body fluids
Term
Ultrafiltration
Definition
Seperation of molecules by weight due to hydrostatic pressure
Term
Absorption
Definition
Food processing in animals. The uptake of small nutrient molecules
Term
Reabsorption
Definition
The recovery of water and solutes from filtrate.
Term
Secretion
Definition
Discharge of waste from the body fluid into the filtrate
Term
Urine
Definition
Waste and water. Hyperosmotic to blood.
Term
Hypothalamus
Definition
Secrete ADH, and monitor the osmolarity of blood and regulate the release of ADH from the posterior pituitary.
Term
Pituitary, posterior
Definition
Stores and releases hormones.
Term
ADH
Definition

Antidiuretic Hormone (vasopressin). Makes epithelium of collecting duct more permeable to water. Increasing water reabsorption, concentratiating and reducing the volume of urine, lowers blood osmolarity back toward the set point. 

ADH is a response to an increase in blood osmolarity. Helps when dehydrated. ADH can lower blood Naconcentration by stimulating water intake.

Term
RAAS
Definition

Renin-angiotensin-aldosterone system. Hormone cascade that helps regulate blood pressure.

Released by Juxtaglomerular apparatus (JGA) in response to a drop in both blood volume and pressure . When the body losses both salt and body fluid, not changing osmolarity. RAAS helps maintain set point by stimlating Na+ reabsorption.

Term
Aldosterone
Definition
A hormone that acts on the nephron's distal tubules and collecting duct, making them reabsorb more Na+ and water, thus increasing blood volume and pressure.
Term
Angiotensinogen
Definition
Cleaved by renin to create Angiotensin I. Angiotensin converting enzyme (ACE) splits off two amino acids from angiotensin I to form angiotensin II.
Term
Angiotensin II
Definition
Raises blood pressure by consricting arterioes, decreasing blood flow to man capillaries, including those of the kidney. It also stimulates the adrenal gland to release aldosterone.
Term
Countercurrent exchange.
Definition
Occurs between two fluids seperated by one or more membranes and flowing in opposite directions.
Term
Rete Mirabile
Definition
A complex of arteries and veins lying close to each other. Used in countercurrent exchange.
Term
Juxtamedullary nephron.
Definition
Go deeper into the renal medulla. This creates a more concnetrated, hyperosmotic, solution. Important in the creation of urine.
Term
Gills of teleosts
Definition
In the gills, specialized chloride cells actively transport chloride ion in and out, Na+ follows passively. In marine animals, Cl is pumped out while freshwater fish pum Cl in.
Term
Salt glands
Definition
Used to secrete salt. Countercurrent exchange is used to remove salt from blood by transport epithelia. Salt is released through ducts to the nostril.
Term
Elasmobranch osmoregulation
Definition
Cartilaginous animals have an internal salt concentration much lower than that of seawater. Salt tends to diffuse into their bodies from the water. Their skin contains high concentrations of urea, a nitrogenous waste product of protein and nucleic acid metabolism, and trimethylamine oxide (TMAO) a molecule that protects proteins from damage by urea.
Term
Agglutination
Definition
Clumping of antibodies
Term
Neutralization
Definition
Antibodies attach to virus so they can't attach to cells.
Term
Precipitation
Definition
Soluble antigens react with soluble antibodies to create an insoluble product
Term
Complement fixation
Definition
Test for certain antibodies and antigens.
Term
Opsonization
Definition
Binding of antibodies to antigens on the surface of bacteri promotes phagocytosis by macrophages and neutrophils.
Term
Immunodeficiency
Definition
A disorder in which an immune system response to antigens is deficient or absent.
Term
Autoimmune disease
Definition
Immune system attacks healty self cells as a result of no self-tolerance
Term
Vaccination
Definition
Artificial exposure to a pathogen inducing active immunity
Term
Passive immunity
Definition

Short term immunity as a result of the trasfer of antibodies. 

Maternal antibodies from mother to fetus or nursing infant.

Term
Active immunity
Definition
Long term immunity from B and T memory cells. Can result from exposure or vaccination.
Term
APC
Definition

Antigen Presenting Cell.

Have MHC II. Important for activation. Dendritic cells, macrophages and some B cells.

Term
TCD4
Definition
T Helper Cells with CD4 Protein. Activate B-cells and Cytotoxic T Lymphocytes (CTL)
Term
TCD8
Definition
Cytotoxic T lymphocytes (CTL) with CD8 protein. Bind to infected cells MHC I and kill with perforin and granzymes.
Term
NK
Definition
Natural Killer Cells. Cells circulate through the body and detect abnormal array of surface proteins. They release chemicals that lead to cell death. Non selective.
Term
B memory
Definition
B-cell response shortcut
Term
Tmemory
Definition
T cell response shortcut
Term
B plasma cells
Definition
B cell effector cells. Proliferated by activated B lymphocytes, and produced soluble antigen receptors, antibodies.
Term
Cell mediated
Definition
Activated t helper cells produced cytokines that actiavte cytotoxic t cells (CTL.) CTLs bind to infected cells at the class I major histocompatibility (MHC) molecule and CD8 accessory protein. CTLs secrete perforin to form pores in the infected cells and granzymes to break down proteins.
Term
Antibody-mediated
Definition

(Humoral)

Activated T helpper  cells bind to antigen presented on MHC II of B-cell and produced cytokines that activate B-cell and stimulate proliferation of b-cells which produced plasma cells (and b mem cells) Plasma cells secrete antibodies (soluble antigen receptors) into the fluids.

Term
AIDS
Definition
Acquire immunodeficiency syndrome
Term
HIV
Definition

Human immunodeficiency virus

Retrovirus, attacks CD4 of Th cell

Term
Salk polioo vaccines
Definition
Killed, take more than once.
Term
Sabin polio vaccine
Definition
Attenuated, alive. Taken only once. Chance of getting polio.
Term
Primary
Definition
First exposure
Term
Secondary
Definition
Second exposure, memory cells.
Term
Colostrum
Definition

Milk. 

Ig A (some IgM/igG)

Term
Neonate immunity
Definition
Ig G
Term
Clonal selection
Definition
Killing of certain clonal colonies that would attack self. Integral a functional immune system.
Term
Neuron
Definition
Fundamental unit of the nervous system, conduct signals via electric charge across its plasma membrane
Term
Myelinated
Definition
In white matter
Term
Unmyelinated
Definition
In grey matter
Term
Schwann cells
Definition
Type of glial cell that forms insulating myelin sheath around axons of neuron in the PNS
Term
Nodes of Ranvier
Definition
Gap in myelin sheath of axons where an action potential may be produced
Term
Neurilemma
Definition
Membrane around neuron (Myelin sheath)
Term
Axon
Definition
Long process of nerve fiver that conducts impulses away from body of nerve cell.
Term
Dendrite
Definition
Numerous short branched extensions of a neuron that receive signals from other neurons
Term
Nerve cell body
Definition
Part of neuron that includes the nucleus, excludes the process.
Term
Oligodenrocyte
Definition
A type of glial cell that forms insulating myelin sheaths around the axon of neurons in the CNS
Term
Astrocyte
Definition
A glial cell with diverse functions, providing structural support for neurons, regulating the interstitial environment, facilitating synaptic transmissions and assisting in regulating the blood supply to the brain
Term
Neuroglia
Definition
The supporting structure of nervous tissue, consisting of a fine web of tissues enclosing neurglial cells.
Term
Membrane potential
Definition
The difference in voltage between the inside of the cell and the surrounding matter.
Term
Action Potentials
Definition
+30 mV. Voltage where all Na gates open, and neuron fires. All or nothing stage.
Term
One-way propogation
Definition
Due to refractory hyperpolarization. Presynaptic neuron won't fire even if stimulus is applied.
Term
Refractory periods
Definition
Occurs during repolarization, neuron won't fire even if stimulus is applied
Term
Salatory conduction
Definition
Action potential jumping from one node of ranvier to the other. Is rapid transmission of nerve impulse along axon.
Term
Cable properties
Definition

1-2mm Max.

Either really thick, or insulated. We have insulated.

Term
Action potential propagation
Definition
One action potential induces another.
Term
Axon
Definition
Long process of nerve fiber that conducts impulses away from body of nerve cell.
Term
Dendrite
Definition
Can receive signals from other molecules, but cannot conduct.
Term
Nerve cell body
Definition
Can receive signals from other molecules, but cannot conduct.
Term
Axon Hillock
Definition
Beginning of axon where action potential is intiated
Term
Synpase
Definition
Structure that passes neurotransmitter to other neuron
Term
Synpatic Gap
Definition

(Cleft)

Gap between presynpatic neurons synpase and postsynaptic neuron

Term
Neuromuscular junctions
Definition
The site where motor neurons synapse with muscle cells
Term
Motor end plates
Definition
Site at which nerve impulses are received by muscles
Term
Synaptic vesicles
Definition
Membrane bound compartments containing neurotransmitters
Term
Ca2+ ions
Definition
Function as a second messenger. All cells maintin extracellular Ca2+ 1k to 10k X intracellular Ca2+
Term
ATPase
Definition
Na+/K+ channel or carrier proteins. Cleaves ATP and release energy.
Term
ACH
Definition
Neurotransmitter released at synaptic terminal, diffuses across synpatic cleft and binds to receptor proteins on muscle fiber's plasma membrane, triggering an action potential in muscle fiber.
Term
ACHase
Definition

Acetylcholinesterase

Hydrolyzes ACH. Serves to terminate synaptic transmission.

Term
Na+/K+ pump
Definition
Actively transport Na+ or K+ into or out of the cell.
Term
Resting potential
Definition
=65mV to -85mV. Has polarized cell membrane. Na gates close K gates close by are "leaky"
Term
Depolarization
Definition

Na+ gates open as voltages change-->Na+ diffuses into cell-->inside of cell becomes more positive. Leads to Threshold -- About -55mV. Threshold-->all Na+ gates open-->Na+ rushes in-->Action potential is reached -- usually +30mv.

Term
Polorization
Definition
Closer to equilibrium concentrations. 3 extracellular Na+ for every 2 intracellular K+.
Term
Repolarization
Definition
Re-establishment of resting potential after firing. AP-->All Na+ gates closed and all K+ gates open-->K+rapidly diffuses out of cell-->inside of cell becomes more negative-->K+ gates closed-->Na+/K+ pumps re-establish resting potential.
Term
Hyperpolarization
Definition
During repolarization. Membrane can become more negative than resting potential.
Term
Concentration
Definition
The concentration of solutes (K, Na, etc.)
Term
Electrical gradient
Definition
Difference in electrical charge between inside the cell and outside.
Term
Cholinergic synpases
Definition
Synapses that use acetylcholine
Term
Presynaptic Neurons
Definition
Refers to the neuron that is firing
Term
Postsynaptic Neurons
Definition
Refers to the neuron receiving the charge
Term
Synaptic vesicles
Definition
Membrane bound compartments containing neurotransmitters.
Term
Receptor proteins
Definition
Ligand-gated channels
Term
Synapse
Definition
End of presynaptic axon
Term
IPSP's
Definition
Inhibitory postsynaptic potential. Hyperpolarization of postsynaptic neuron as a result of opening of ligand-gated ion channel that is selectively permeable K+ or Cl- only
Term
EPSP's
Definition
Excitatory postsynaptic potential. Depolarization, membrane potential is brought closer to action potential. Na+ gates and K+ gates are activated.
Term
Summation
Definition
Combination of IPSP or EPSP to either bring closer or farther away from threshold
Term
Gradation
Definition
Shifts in membrane potential
Term
Neural inhibition
Definition
Bind to Cl- gates lowering the charge farther from threshold
Term
Neuropeptide
Definition
Relatively short chain of amino acids that serve as a neurotransmitter. Mediates perception of pain, involves endorphins.
Term
Second Messenger
Definition
Signal transduction. Part of metabotropic receptors.
Term
cAMP
Definition

Cyclic AMP

Part of metabotropic receptor. Neurotransmitter-receptor complex activates a G protein which in turn activates adenylyl cyclase, an enzyme that converts ATP to cAMP. cAMP activates protein kinase A, which phosphorylates specific ion channel proteins in the postsynaptic membrane, causing them to open or close. Because of the amplifying effect of the signal transduction pathway, the binding of neurotransmitter molecule to a metabotropic receptor can open or close many channels.

Term
ATP
Definition
Used in active transport. K+ and Na+ pumps
Term
GABA
Definition
Gamma-aminobutyric acid, IPSP, amino acid neurotransmitter. Binding of GABA to receptors in postsynaptic cells increases membrane permeability to  Cl-, resulting in an IPSP.
Term
Seratonin
Definition
Biogenic anine, neurotransmitter. Made from trryptophan, affect sleep, mood, attention and learning
Term
Beta-blockers
Definition
Class of drugs that inhibits a response to adrenaline
Term
Lonotropic receptors
Definition
Ligand-gated ion channel. Transmembrane protein that opens or closes in response to a signaling molecule (ligand/neurotransmitter) allowing flow of specific ions.
Term
Metabotropic Receptors
Definition
Activates a signal transduction pathway in the postsynaptic cell involving a second messenger
Term
Ligand regulated channels/gates
Definition
Gates on postsynaptic neuron that are regulated by neurotransmitters excreted by presynaptic neuron
Term
Voltage regulated channels/gates
Definition
Propagation of action potential from presynaptic to postsynaptic uses voltage
Term
Anatomy of muscle tissue
Definition

Skeletal muscle is made up of muscle fibers. The muscle fibers are made up of myofibrils. Myofibrils are made up of thin filaments (actin) and thick filaments (myosin)

 

Term
Sarcomere shortening
Definition
Sliding of the actin (thin filaments) towards the M lines and the myosin (thick filaments) towards the Z line
Term
Sarcomere
Definition
Sections of myofibrils. Made of thick filaments, myosin and thin filaments actin. The borders of the sarcomere are lined up in adjacent myofibrils. Thin filaments are attached at the Z lines and project toward the center of the sarcomere while the thick filaments are attached at the M lines centered in the sarcomere.
Term
Calcium
Definition
Calcium concentrations are much lower inside the cell. Arrival of an action potential at a synaptic terminal depolarizes the plasma membrane, opening voltage-gated calcium channels. Ca2+ concentration rises in synapse, causing the synaptic vesicles to fuse with the terminal membrane, releasing the neurotransmitters.
Term
ATP in muscle
Definition
Myosin head can bind ATP and hydrolyze it to ADP and inorganic phosphate. Hydrolysis of ATP converts myosin to a high-energy form. This form of myosin binds to actin forms a cross-bridge, and pulls the thin filament towards the center of sarcomere. The cross-bridge is broken when a new molecule of ATP binds to the myosin head.
Term
Creatine phosphate
Definition
Transfer of a phosphate group from creatine phosphate to ADP in an enzyme-catalyzed reaction synthesizes additional ATP.
Term
Neuromuscular junction
Definition
The site of where motor neurons synapse with skeletal muscle cells.
Term
ATPase
Definition
Turns ATP to ADP and Pi
Term
Myoglobin
Definition
Oxygen storing, pigmented protein in muscle cells.
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