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96 Cards in this Set

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What is the purpose of the circulatory system?
transport nutrients, respiratory gases, hormones, metabolic products, etc throughout body; temperature control
What are the structural elements of the circulatory system?
Pump (heart), conduits (vessels), transport medium (blood)
Where does de/oxygenated blood flow in a vertebrate?
Deoxygenated to gills or lungs to get oxygen, oxygenated to rest of body (systemic)
Where does the right side of the heart pump blood to (looking at heart, is left)
To the lungs
Where does the left side of the heart pump blood to (looking at heart, is right)
To the rest of the body
What prevents backflow of blood into heart?
Valves
What is systole?
The contraction phase of the heart
What is diastole?
The relaxation phase of the heart
What makes the heart sounds?
Heart valves closing
What does effective heart pumping require?
Sequential contraction of chambers, coordinated contraction of muscle cells within chamber
Are cardiac muscle striated?
Yes
Why are cardiac muscles striated?
The arrangement of actin and myosin filaments are aligned at regular intervals; muscle contraction depends on these filaments sliding past each other
What do the chambers in the heart depend on for regular contractions?
Specialized cells in the sinoatrial node, atrioventricular node, and Bundle of His and Purkinje fibers
What cells initiate heartbeats?
Pacemaker cells in sinoatrial node
How are contractions of muscle cells coordinated in chambers?
Gap junctions allow electrical continuity which leads to rapid spread of action potential
What ion channels are involved in heart action potenetials?
Na+ and Ca2+
What are mechanisms for regulation in the heart?
Specific electrical events
What does P stand for on an ECG graph?
Atrial depolarization
QRS?
Depolarization of ventricles
T?
Relaxation and repolarization of ventricles
What are some abnormal ECGs?
Accelerated, Uncoordinated contraction, blockage of electrical system
What are sympathetic nerves?
Release (nor)epinephrine to increase heart rate (fight or flight mode)
What are parasympathetic nerves?
Release acetylcholine, decrease pacemaker activity, which slows heart rate (rest and digest)
How does norepinephrine effect action potentials?
Makes Na+ and Ca2+ more permeable, so resting potential rises quicker and action potentials are closer together
How does acetylcholine effect action potentials?
Decreases permeability of Na+ and Ca2+, so resting potential rises more slowly, and action potentials are farther apart
What are the five different types of vessels in the circulatory system?
Arteries, arterioles, capillaries, venules, and veins
In what order do the vessels proceed, starting from the heart?
Arteries, arterioles, capillaries, venules, veins
What are arteries and arterioles composed of?
Elastic fibers to withstand high pressure, smooth muscle cells for contraction and expansion (altering blood flow and resistance)
What are veins composed of?
Valves to prevent backflow
What controls blood flow to capillaries?
Precapillary sphincter in arterioles
What controls direction of blood?
Balance between blood pressure and osmotic pressure; squeezed out of capillary via blood pressure, pulled back in via osmotic pressure
What helps carry blood back to the heart?
Skeletal muscles contractions (and gravity), help veins and lymphatic vessels carry blood and fluid back to the heart
What is blood composed of?
Plasma, red blood cells, white blood cells, and platelets
What promotes diffusion in the alveoli?
Rapid movement of blood through surrounding capillaries which maintains CO2 and O2 concentration gradients
What increases the O2 capacity of blood?
Hemoglobin (x60)
What is the binding of O2 to hemoglobin dependent on?
The pressure of O2
What is red blood cell production stimulated by?
Low oxygen content in tissues (transcription factor HIF-1, kidney produces erythropoeitan which stimulates stem cells in bone marrow)
How is CO2 removed from tissues?
Carbonic anhydrase maintains CO2 gradient from cells (high) to plasma (low); some CO2 complexes with deoxygenated HgB
What is the purpose of the excretory systems?
Filtration and to maintain osmotic balance
Why does blood require filtration?
Since blood carries nutrients AND waste, it requires filtration to get rid of the garbage
What are the waste products of metabolism?
Nitrogenous products
What are the vertebrate excretory systems composed of?
Kidneys
What is the functional unit of the kidney?
The nephron unit
What is the nephron unit composed of?
Renal corpuscle, Renal tubule, Collecting duct
What is the renal corpuscle and what does it do?
Glomerulus, and Bowman's capsule, filtration site
What is the renal tubule and what does it do?
Site of tubular secretion and absorption, surrounded by capillaries;
What is the collecting duct and what does it do?
Site of urine processing; concentration or dilution
What does the concentrating ability of the mammalian kidney depend on?
It's anatomy; entry/exit on the concave side, nephrons regularly arranged within the kidney
How are nephrons arranged in kidney?
Glomeruli in cortex; renal tubules loop through medulla; collecting ducts start at cortex, pass through medulla, empty into ureter
Where is most of the volume of blood reabsorbed?
The proximal tubule
What are the glomeruli?
Highly permeable capillary beds
What are podocytes?
Surface cells of Bowman's capsule;
What do the Bowman's capsules surround?
The glomeruli
What are the specialized zones of the renal tubule?
Proximal convoluted tubule; loop of Henle; distal convoluted tubule; collecting duct
What is the function of the proximal convoluted tubule?
Transports NaCl out of tubular fluid and H2O follows; also transports glucose and amino acids out of tubular fluid
What is the function of the loop of Henle?
Permeable to H2O and small molecules
What is the function of the distal convoluted tubule?
Transports NaCl out of tubular fluid
What is the function of the collecting duct?
Urine concentration through osmosis, little active transport
What regulates the pH in the kidney and how?
Secretion of H+ and reabsorption of bicarbonate
What is the structure of the proximal convoluted tubule?
Microvilli on cells on lumen face; many mitochondria for active transport
What part of the kidney is a counter-current multiplier?
The loop of Henle
What does countercurrent exchange in the kidney do?
Creates a concentration gradient in the medulla
What does the degree of urine concentration depend on?
The magnitude of the gradient in the collecting duct
What are aquaporins?
Family of water channels; integral membrane proteins that form water-selective channels; expressed in tissues with high water permeability
What disease can result from a mutation in aquaporins?
Diabetes insipidus
What does local autoregulation in the kidneys do?
Incoming renal arterioles dilate to maintain flow through capillaries if systemic pressure increases
What is the renin-angiostensin-aldosterone system?
Response to decreased blood volume and blood pressure, increases local and systemic blood pressure by effects on vessels and fluid intake
How is blood pressure regulated by systemic systems?
ADH system as a response to increases osmolarity; increase water reabsorption to concentrate urine; increases water permeability of collecting duct via effects on aquaporin content
What are responses in the case of low blood pressure?
RAA and ADH
What are the responses in the case of high blood pressure?
Atrial natriuretic peptide (ANP) decreases salt and water uptake
What is a sensory cell?
A modified neuron (receptor cell)
What do sensory cells do?
Transduce physical or chemical stimuli into signals that are transmittable and interpretable
How do the sensory cells detect a stimulus?
Membrane receptor proteins detect a stimulus and respond by altering the flow of ions across the plasma membrane
How is the intensity of the stimulus recorded?
The frequency of the action potentials produced
How is the energy from a stimulus transduced?
Made into action potentials by opening or closing of ion channels
What do sensory cells form?
Sensory organs (eyes, nose, ears, etc)
What determines what a stimulus is interpreted as?
It depends on which cells in the CNS receive the signal
What is ionotropic sensory detection?
Receptor protein is part of ion channel and by changing its conformation, opens/closes the channel pore
What is metabotropic sensory detection?
Receptor protein is linked to a G protein that activates a cascade of intracellular events that eventually open/close ion channels
What is adaptation?
When a sensory cell responds less when stimulation is repeated
What does olfaction depend on?
Chemoreceptors
Where are olfactory sensors in vertebrates?
Neurons embedded in epithelial cells in nasal cavity
What is the sequence following an odorant binding to olfactory receptor proteins?
G protein activated, activates enzyme that increases the level of the second messenger cAMP, cAMP opens Ca2+ channel, leads to opening of Cl- channel which depolarizes the membrane potential and action potential fired
What provides for the identification of almost limitless number of different odorant molecules?
Most odorants activate more than one type of olfactory receptor
What is gustation?
Sense of taste
What are papillae?
Raised bumps on human tongues
What increases the surface area of taste buds?
Microvilli
What are the five basic tastes a taste bud can detect?
Sweet, Bitter, Umami (savory), Salty, and Sour
Which tastes are detected by ion channels, and which by G-protein coupled receptors?
Ion: Salty and Sour
G-protein: Sweet, Bitter, Umami
What are mechanoreceptors?
Cells sensitive to mechanical forces
What causes mechanoreceptors to recognize a stimulus?
Distortion of the plasma membrane causes ion channels to open
What are Merkel's discs?
Provide continuous information about things touching the skin
Meissener's corpuscles?
Very sensitive mechanoreceptors found mostly in non-hairy skin. Adapt rapidly and provide info on changes in things touching skin
Ruffini endings?
Provide info about vibrating stimuli of low frequencies
Pacinian corpuscles?
Provide info on vibrating stimuli of higher frequencies
What are stereocilia?
Like microvilli; when bent in one direction, receptor potential is pos; vice versa