• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/313

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

313 Cards in this Set

  • Front
  • Back
Does increased EDV increase or decrease ventricular contraction?
increase
T or F. The heart will always pump whatever it receives.
F. Not always. Within limits it will.
Which part of the heart prevents decomposition?
the pericardium
How does posture affect venous return?
raising arms improves venous return, venous pooling decreases it
Which factors decrease during an acute hemorrhage?
SV, CO and MAP
How can you prevent the heart from going into decomposition? (POSSIBLE SHORT ANSWER?)
blood letting via leeches
Are ESV and SV proportional or inversely proportional?
inversely proportional
How much blood does the ventricle hold when filled?
130 ml
How much blood is in the ventricle after systole?
60 ml
How much blood is ejected from the heart?
70 ml
What happens when the overlap of actin and myosin in the heart is not optimal?
decomposition
afterload?
??
The PSNS can ____ contractility via ___ receptors.
decrease, M2
Epinephrine can ____ contractility via ____ receptors.
increase, Beta1
Does SNS activity lead to an increase or decrease in SV?
increase (at any given EDV)
T or F. The PSNS and epinephrine affect SV similarly.
False. The SNS and epinephrine both increase SV, the PSNS decreases it.
How do the SNS and epinephrine increase contractility?
1. Increase Ca2+ entry from ECF
2. Increase rate of myosin ATPase activity
3. Increase rate of Ca2+ reuptake by sarcoplasmic reticulum
Which factor(s) decrease(s) during mild exercise?
TPR
T or F. MAP increases greatly during mild exercise.
False. MAP does not change very much.
What is the role of the baroreceptors?
to keep systemic MAP as close to 100 mmHg as possible
Are baroreceptor reflexes short or long term regulators of MAP?
short-term
Where are the arterial baroreceptors located?
carotid sinus & aortic arch
Baroreceptors are also known as ______ receptors.
stretch
Arterial pressure increases as action potential frequency _______.
increases
What happens to sympathetic and parasympathetic activity during a compensatory response?
sympathetic activity increases, parasympathetic activity decreases
T or F. Due to a compensatory response, MAP returns to normal shortly after an actue hemorrhage.
F. It does not quite reach the normal value. There is a persistent error signal.
T or F. Baroreceptors help to restore blood plasma volume.
T. They facilitate reabsorption of fluid from the interstitial space and lymph.
T or F. Kidneys help maintain body pH.
True
How is glucose produced in the kidneys?
Via gluconeogenesis (opposite of glycolysis). Glucose is made form amino acids during fasting.
T or F. Ureters lack smooth muscle and are composed mainly of cartilage and epithelial cells.
F. Ureters contain smooth muscle which allows wave-like contractions to help conduct urine from the kidney to the bladder.
Where is epinephrine produced?
in the adrenal gland
Is the PSNS active or inactive while the bladder fills?
inactive
Is the SNS active or inactive while the bladder fills?
active
Is the somatic NS active or inactive while the bladder fills?
active
The detrusor is under the control of the ___ NS.
PS
The external urethral sphincter is under the control of the ___ NS.
somatic
The internal urethral sphincter is under the control of the __ NS.
S
What induces the micturition reflex?
stretch receptors in the bladder
When the micturition reflex is voluntary, the signal from the stretch receptors is routed through the ______________.
cerebral cortex
When the micturition reflex is involuntary, the signal from the stretch receptors is routed through the ______________.
spinal cord
T or F. The osmolarity outside the nephron gets higher and higher.
True
Approx. how many nephrons are in the human body?
2-3 million
T or F. The urine is fully formed by the time it leaves the nephron.
True
T or F. The glomerulus receives the primary urine via filtration.
F. The Bowman's capsule receives the primary urine by filtration from the glomerulus
Which is the largest part of the nephron?
PCT
Where in the nephron does the majority of reabsorption and secretion occur?
PCT
What is the role of the loop of Henle?
concentrates urine, conserves H20, establishes medullary osmotic gradient
Which components of the nephron are part of the counter-current system?
loop of henle & CCD
Where is the majority of K+ secreted?
DCT & CCD
Where does variability in reabsorption and secretion in the nephron occur and why?
DCT & CCD; due to hormone actions
Which hormones affect reabsorption and secretion in the nephron?
aldosterone, ADH/vasopressin, ANH, angiotensin II
What is the 1st important site of vascular resistance control in the nephron?
afferent arteriole
Where is the 2nd important site of vascular resistance control in the nephron?
efferent arteriole
Where is the 2nd capillary bed and site of reabsorption and secretion in the nephron?
peritubular capillary bed & vasa recta
T or F. Glomerular filtration is an active process.
F. Passive due to Starling-Landis forces
T or F. Tubular reabsorption can be both active and passive.
T. Many active transport processes for ions and nutrients as well as passive diffusion for ions and nutriets (osmosis for H20).
Is tubular secretion active or passive?
active
How much of the plasma flowing through the glomerular capillaries is filtered to form the primary urine?
20%
What is faster: the rate of plasma flow or the GFR?
plasma flow
T or F. The primary urine contains protein.
False
How much plasma is filtered per day?
180 L
How often is the entire plasma volume filtered?
every 25 mins
How much urine is excreted daily?
1.5 L
T or F. The kidney can excrete virtually any waste or foreign substance.
True.
What is the role of the basement membrane matrix?
has a negative charge which repels proteins
T or F. The pressure after a resistance is higher than the pressure before the resistance.
False. The pressure after a resistance is lower than the pressure before a resistance.
Which Starling-Landis forces favor filtration?
Pgc and Pibc
T or F. Constricting the efferent arteriole causes GFR to increase.
True.
T or F. Pgc increases as GFR decreases.
False. Pgc increases as GFR increases.
T or F. Increasing resistance decreases Pgc and GFR.
True.
How is Pcap/Pgc controlled intrinsically?
myogenic response and paracrine
Ca2+ channels open when the afferent arteriole is stretched causing the arteriole smooth muscle to _____. This is an example of ____ control of GFR.
constrict; intrinsic
Which NS is involved in extrinsic control of GFR?
SNS
A drop in MAP causes a(n) ____ in SNS output resulting in ______ of afferent and efferent arterioles. The overalll effect is a(n) ____ in Pcap and GFR. This is an example of ____ control of GFR.
increase; constriction;decrease; extrinsic
How much of the BMR of the whole body are the kidneys responsible for?
20%
T or F. The urine of a healthy individual does not contain glucose.
True.
What is the primary barrier for reabsorption in the kidney?
tubule epithelia
T or F. Paracellular transport between epithelial cells is an important part of reabsorption in the kidney.
False. Paracellular transport is restricted by tight junctions.
Which part(s) of the nephron has/have the most microvilli and why?
proximal tubules; high SA for reabsorption
Which part(s) of the nephron has/have the tightest tight junctions?
DCT and CCD
Which part(s) of the nephron has/have the most mitochondria and why?
PT due to many active transport processes
T or F. Clearance rates can be used to estimate GFR and renal blood flow.
True.
T or F. H20 is completely reabsorbed.
False. Largely but not completely reabsorbed.
T or F. PAH (para-amino hippuric acid) is completely reabsorbed.
False. It is completely cleared from the blood.
Is inulin net secreted or net reabsorbed??
neither
Is urea net secreted or net reabsorbed?
44% reabsorbed therefore net secreted
If CRx >1 then the substance is net _____.
secreted
T or F. Na+ follows Cl- passively.
False. Cl- follows Na+ passively.
Where is the majority of Na+ reabsorbed?
PT
Where does passive H2O reabsorption oocccur?
in the CCD (via osmosis)
Tubular fluid is _____-osmotic to the medulla.
hypo
T or F. The counter current multiplier system (loop of Henle) creates a high osmotic gradient in the ISF and blood vessels.
True.
The PT is ______-osmotic to the cortex.
iso (due to leaky tight junctions)
Which limb of the loop of Henle is permeable to H2O and why?
descending limb due to presence of aquaporins
What is urine like when the DCT and CCD are impermeable to H2O?
dilute (low osmolarity), high volume
In the proximal tubule, active transport occurs in the _____ membrane and drives secondary active transport in the ______ membrane.
basolateral; apical
When is aldosterone released and from where?
in response to low NaCl in the ECF or indirectly by a fall in blood volume, released from the adrenal cortex
Where does aldosterone bind?
to a cytoplasmic receptor in principal cells
What happens when aldosterone activates a cytoplasmic receptor?
Na+ and K+ channels in the apical membrane open, more Na+ and K+ channels are synthesiszed, more Na+/K+ ATPases are synthesized
Where are Na+/K+ ATPasees located?
in the basolateral membrane
What is the overall effect of aldosterone?
increases permeability of DT/CCD to Na+, increase NaCl reaborption and K+ secretion, increased water reabsorption, increased blood volume, increased blood pressure
T or F. Na+ reabsorption is coupled to K+ secretion
True.
Which cells secrete renin?
granular/juxtaglomerular cells
T or F. Angiotensinogen is always present in large amounts in the plasma.
True.
What is the role of renin?
cleaves angiotensinogen to angiotensin I
What is the role of ACE?
cleaves angiotensin I to angiotensin II
What is the role of angiotensin II?
stimulates aldosterone release from adrenal cortex, increasing Na+ reabsorption
T or F. Angiotensin II increases vasoconstriction, aldosterone secretione, ADH secretion, thirst stimulation and MAP.
True.
When is urine flow rate the highest?
When ADH and aldosterone is low.
When is urine [NaCl] highest?
When ADH is high and aldosterone is low.
Is high ADH associated with high or low urine flow rate?
low
T or F. High aldosterone is associated with low urine flow rate.
False. It is associated with low urine [NaCl].
When is ANH released?
in response to high venous filling pressure (usually associated with high NaCl content in the body)
How does ANH impact NaCl content in the body and GFR?
increases NaCl and H2O excretion by raising GFR and inhibiting active Na+ reabsorption
What is the afferent division of the PNS?
information conducted from external and internal sensors to CNS
T or F. Integration occurs in the PNS.
False. CNS
What do visceral neurons detect?
sensory information from with8in the body
T or F. Baroreceptors are sensory neurons.
False. Visceral
What do proprioreceptors detect?
position of limbs and the body
Which NS is associated with voluntary activity? (somatic NS or autonomic NS)
somatic NS
Which NS is associated with excitatory info only? (somatic NS or autonomic NS)
somatic NS
Which NS is associated with neurons which reguate internal organs and structures? (somatic NS or autonomic NS)
autonomic NS
Which cells account for 90% of the cells of the nervous system?
glial cells
Which part of the neuron is responsible for metabolic functions?
the cell body/soma
Where does most integration in a neuron occur?
axon hillock
When is a pre-synaptic neuron not a pre-synaptic neuron?
When it is a post-synaptic neuron.
What is the range in length of a human neuron?
1mm-1m
What are the 3 structural classes of neurons?
bipolar, pseudo-unipolar, multipolar
Which glial cells are primarily found in the CNS?
oligodendrocytes
Where are schwann cells most numerous?
in the PNS
Where are glial cells often wrapped around multiple axons?
CNS
T or F. Glial cells can take up neurotransmitters and remove that signal.
True.
Which 3 things are membrane potentials associated with?
1. unequal distribution of ions across membranes
2. Active transport mechanism
3. differential permeability of the membrane to different ions
How many ions move to result in a membrane potential?
less than 1/100 000
Is the conductance of K+ or Na+ greater?
K+
Which ion plays a major role in establishing a negative resting membrane potential?
K+
How is membrane leakage counteracted?
by the Na+/K+ ATPase
What information does Eion represent?
whether chemical or electrical driving forces predominate for that ion
What is the equilibrium potential for K+?
-94 mV
What is the equilibrium potential for Cl-?
-80 mV
What is the equilibrium potential for Na+?
+ 60 mV
The driving force for diffusion is greatest for which ion?
Na+
Depolarization occurs when the membrane potential becomes more ______.
positive
How are GPs conducted away from the site of origin and how are they affected as they move further away?
decremental local flow; decrease in size
T or F. The size of the GP depends on the size of the stimulus.
True.
T or F. Opening of K+ or Cl- channels results in depolarization.
False. Hyperpolarization
Which channel(s) open(s) at excitatory synapses and what is the net effect?
Na+ and K+; depolarization
What is the charge of a single EPSP?
+ 0.5 mV
What happens as Vm approaches threshold?
Na+ channels start to open
What happens when Vm reaches threshold?
voltage gated Na+ channels open explosively (+ feedback loop)
What is the membrane potential at threshold?
-55 mV
What happens when Vm reaches +30 mV?
voltage-gated Na+ channels close and voltage-gated K+ channels open
Why does hyperpolarization occur?
some voltage-gated K+ channels are slow to close
How does Vm return to resting after hyperpolarization
mostly due to K+ leak channels
Na+ channels are ____ or _____ during the refractory period.
open; inactivated
T or F. The absolute refractory period is longer than the relative refractory period.
False.
During which refractory period is a greater than normal stimulus required to generate another AP?
relative
T or F. Phasic receptors adapt very slowly.
False. Tonic receptors adapt very slowly
T or F. Tonic receptors are generally associated with life-critical sensation such as pain.
True
Which receptors detect changes in the environment? (tonic or phasic)
Phasic
What prevents an AP from moving backwards?
the absolute refractory period
T or F. APs are relatively rapid events.
False.
What allows APs to travel at the speed of electricity?
saltatory propagation from one node to another
T or F. The larger the diameter of an axon, the faster the propagation.
True
Saltatory propagation accelates AP conduction velocity up to _____ times.
1000
T or F. Decremental local current flow is not effective over longer distances in myelinated axons due to insulation.
False. It is effective.
What are the advantages of electrical synapses via gap junctions?
high speed, low cost
What are the advantages of chemical synapses?
rectifying, facilitate integration
Which synapses are most common in cardiac and smooth muscle?
electrical synapses
Which synapses are most common in the nervous system?
chemical synapses
T or F. Arrival of an AP opens voltage-gated Ca2+ channels.
True
What is the cause of 90% of the delay in chemical synapses?
docking of synaptic vesicalse (upon activation by Ca2+) and release of n/t into synaptic cleft by exocytosis
What is the cause of 10% of the delay in chemical synapses?
diffusion of n/t across synaptic cleft
Which mechanisms decrease n/t concentration in the cleft?
1. active transport of n/t back into pre-synaptic membrane for re-packaging into vesicles
2. n/t diffuses away from cleft
3. n/t actively taken up and metabolized by glial cells
Where is the all or none law valid?
in the neuromuscular junction
T or F. Contact area, amount of n/t released and number of receptors are greater in neuron-neuron synapses than in the synapse between a somatic motor neuron and a skeletal muscle cell.
False.
T or F. The all or none rule always applies to neuro-muscular junctions due to integration.
False. There is no capacity for integration. So much acetylcholine is released that one E.P.P (GP on post syn membrane) is +50mV (suprathresold)
T or F. Gas exchange occurs in the conducting zone.
False. Respiratory zone.
Which zone has more cartilage, the conducting or the respiratory zone?
conducting zone
The SNS releases ______ which acts on _____ receptors to cause broncho_____.
norepinephrine, Beta2 adrenergic, dilation
The PSNS releases _____ which acts on ______ receptors to cause broncho____.
ACh; muscarinic; constriction
What are the functions of the conducting zone?
phonation (larynx), strength (cartilage and smooth muscle), warms air to 37 deg C, humidifies air to 100% R.H., cleanses air
What is the role of alveolar pores?
allow equalization of pressure in the lungs
Which cells secrete surfactant?
type II cells
T or F. The respiratory membrane is more permeable to O2 than to CO2.
False
T or F. The driving force for O2 is greater than the driving force for CO2.
True
What is the role of surfactant?
reduces surface tension up to 90%, prevents collapse of smaller alveoli
T or F. Larger alveoli hold more surfactant due to their higher volume.
False. Surfactant is higher in smaller alveoli.
What is a pneumothorax?
a rupture which connects the intrapleural space to the atmosphere, eliminating outside pressure, making breathing ineffective and causing lung to collapse
T or F. Rebound of chest wall during expiration increases alveolar pressure.
True
When is inhalation active?
During rest and exercise
When is exhalation active?
During exercise
During inhalation, external intercostal muscles pull ribs ____ (up/down) and _____ (in/out), the diaphragm _________ (shortens/lengthens) and moves _______ (up/down). Thoracic volume ________ (increases/decreases) and a ___ (-/+) P is developed.
up; out; shortens; down; increase; -
What do the internal intercostal muscles and abdominal muscles do during exhalation during exercise?
intercostal muscles pull ribs in and down, abdominal muscles push guts in, displacing diaphragm upwards
What does spirometry assess?
pulmonary function
What is the value for tidal volume?
0.5 L
What is the value for inspiration reserve?
3 L
What is the value for expiration reserve?
1.5 L
What is the value for residual volume?
1L
What is the value for inspiration capacity?
3.5 L
What is the value for vital capacity?
5.0 L
What is the value for total lung capacity?
6.0 L
T or F. Minute ventilation is also known as alveolar ventilation.
False. Anat. dead space must be considered for alveolar ventilation.
What makes up the anatomical dead space
stale air which is stuck in the conducting zone and does not participate in gas exchange
T or F. The volume of air in the anatomical dead space is approximately equal to 1.5 L.
False. 150 ml
Aprox. what percentage of alveolar air is replaced per breath?
10%
T or F. Alveolar O2 is much lower and alveolar CO2 is much higher than in outside air.
True.
Is it better to breath more deeply or more quickly?
deeply
T or F. Gases dissolve according to their concentrations.
False. According to their partial pressures.
What is the total pressure of room air?
760 mm Hg
What is the partial pressure of O2?
160 mm Hg
What is the partial pressure of CO2?
0.3 mm Hg
What is the partial pressure of H2O?
0.47 mm Hg
T or F. The partial pressure of O2 is higher in the air than in water.
False. PP is the same in air and water, concentration of O2 in air is higher than in water.
What is the capacity of water to hold O2?
7ml / 1000ml
What is the capacity of air to hold O2?
210 ml / 1000 ml
About how many times more soluble is CO2 in water than O2?
30x
What is the capacity of water to hold CO2? Of air to hold CO2?
0.4; 0.39
T or F. PO2 increases with each step in O2 transport.
False. It decreases
What are PO2 and PCO2 in atmospheric air?
160; 0.3
What are PO2 and PCO2 in alveolar air?
100; 40
What are PO2 and PCO2 in pulmonary arteries?
40; 46
What are PO2 and PCO2 in the cells?
less than or equal to 40; greater or equal to 46
What are PO2 and PCO2 in the systemic arteries?
100; 40
What are PO2 and PCO2 in the systemic veins?
40; 46
What are PO2 and PCO2 in the pulmonary veins?
100; 40
Is diffusion fast or slow at the lungs?
fast
How saturated is Hb as it leaves the lungs?
98%
What happens to Hb at the tissues?
becomes desaturated (deoxyhemoglobin), only 75% of binding sites are occupied by O2
T or F. Hb delivers 4 O2 molecules when it reaches the tissues.
False. One O2. Hb never has 0 O2 mols.
T or F. O2 bound to Hb does not contribute directly to blood PO2.
True. only dissolved O2 does
T or F. The 1st O2 that binds to Hb helps the second which helps the third which helps the fourth.
False. The fourth is not helped.
O2 is a _____ (+/-) allosteric modulator for further O2 binding and a ________(+/-) allosteric modulator of H+, CO2 and phosphate binding.
positive; negative
What happens to the bond between Fe2+ and O2 as temperature increases?
it weakens
What is the shape of the oxygen dissociation curve?
sigmoidal (S-shaped)
What is on the x-axis of the oxygen dissociation curve?
PO2 (driving force)
What is on the y-axis of the oxygen dissociation curve?
% oxygen saturation of hemoglobin
What is the PO2 at the loading point?
100 mm Hg
What is the PO2 at the unloading point at rest? During exercise?
40 mm Hg; 20 mm Hg
What is the % saturation at the unloading point at rest? During exercise?
75% ; 35%
Does the unloading point occur in the systemic veins or the systemic arteries?
veins
Why is the flat region at the top of the oxygen dissociation curve important?
provides an important safety margin for O2 loading during high altitude exposure, respiratory disease and a shift in the curve to the right during exercise
The knee and steep part of the oxygen dissociation curve is important because it allows for a large increase in O2 unloading during exercise for a ______ (large/small) ________ (increase/decrease) in PvO2.
small; decrease
T or F. An increase in the driving force for CO2 shifts the ODC to the right.
True
T or F. An increase in pH shifts the ODC to the right.
False. a decrease in pH (more acidic) shifts the OCD to the rght
T or F. pH increases as CO2 increases.
False. pH decreases
T or F. An increase in blood temperature shifts the curve to the right.
True.
T or F. An increase in RBC [phosphate] shifts the ODC to the right.
True
T or F. O2 loading is improved as the ODC shifts to the right.
False. unloading to the systemic tissues improves
Is fetal or normal Hb more sensitive to 2,3 DPG?
normal Hb
T or F. The fetal Hb curve is shifted to the left of the adult Hb curve.
True
Why isn't the Mb curve S-shaped?
only has 1 binding site for O2
T or F. The Mb curve is found to the left of the adult Hb curve but to the right of the fetal Hb curve.
False. It is to the left of both.
T or F. There is a lot more CO2 than O2 in the blood.
True
How does the majority of CO2 in the body exist?
60% as the HCO3- ion, mainly dissolved in the plasma
T or F. Carbonic anhydrase is the most abundant protein in rbc's.
second most. Hb is the first
T or F. Peripheral chemoreceptors are very sensitive to small changes in PaO2.
False
T or F. H+ does not easily cross the blood-brain barrier.
True
What is the normal pHa range?
7.2 - 7.6
T or F. pH 7 causes coma and pH 7.8 causes tetany of muscles.
True
Which system is able to cope with a change in pHa more quickly, the respiratory or the renal system?
respiratory system
Which system in the body is the only one that is actively physiologically regulated?
bicarbonate buffer system
What is the ratio of [HCO3-] to PaCO2 x aCO2?
20:1
The protein and CO2 buffer systems are in equilibrium with eachother and with all other less important buffer systems by the _____ principle.
isohydric
Hypoventilation occurs when CO2 _______ (production/excretion) exceeds ______ (production/excretion).
production; excretion
Respiratory ______ occurs as a results of hypoventilation.
acidosis
Respiratory _____ occurs as a result of hyperventilation.
alkalosis
Hyperventilation occurs when CO2 ________ (production/excretion) exceeds ______ (production/excretion).
excretion; production
How does the kidney compensate if respiratory acidosis is chronic? If respiratory alkylosis is chronic?
accumulates HCO3- and excreting H+ ; excretes HCO3- and accumulates H+
What is the CO2/HCO3- system (use arrows)?
CO2 + H20 <==> H2CO3 <==> H+ + HCO3-
When HCO3- is lost, metabolic _____ occurs. To compensate, ventilation _____.
acidosis; increases
When H+ is lost, metabolic ____ occurs. Ventilation ____ to compensate.
alkalosis; decreases
T or F. The endocrine system is completely separate from the nervous system.
False
Which complex serves as the neuro-endocrine interface?
the hypothalamus-pituitary complex
What are the 3 classes of hormones?
1. Amines
2. Protein and Polypeptide hormones
3. Steroid hormones
T or F. All amine hormones are derived from tryptophan.
False. Some are derived from tyrosine also.
Name 6 amine hormones.
dopamine, epi, norepi, serotonin,, t3, t4
Which class of hormones are lipophilic (can't be stored in vesicles) and why?
steroid; ring structure of cholesterol preserved
ADH and oxytocin are released from the ____ pituitary.
posterior
The anterior pituitary releases _____________ hormones and _______ hormones.
hypophysiotropic; anterior pituitary
What do hypophysiotropic hormones do?
stimulate the release of another hormone
In which pituitary gland do the axons from the hypothalamus terminate?
posterior
Which type of muscle shows characteristics of both skeletal and smooth muscle?
cardiac muscle
Actin is a ___ filament and mysosin is a ____ filament.
thin; thick
What is the maximum osmolarity of urine and how is it determined?
1400 mOsm ; by the peal osm. of the medulla gradient
Which pathway does ADH activate?
PKA pathway
What does PKA do when activated by ADH?
stimulates production of new aquaporin 2 and insertion of storied aquaproin 2 into the apical membrane of principal cells.... increasing permeability of DCT/CCD to H20, leading to an increase in H2O reabsorption
Where is ADH produced?
in the neurosecretory cells of the hypothalamus
Which receptors stimulate ADH secretion?
osmoreceptors
What generates respiratory rhythm?
I and E neurons and PBC
Where are E neurons located?
in the VRG of the medulla
Which neurons fire during active exhalation, I or E?
E
What does the PBC do?
neurons spontaneously depolarize, driving I neuron firing patterns
Which centre switches off I neurons?
pneumotaxic
Which centre prevents I neurons from switching off?
apneustic center
What do peripheral chemoreceptors monitor?
PaO2, pH and PaCO2
What do central chemoreceptors monitor?
PaCO2
T or F. Peripheral chemoreceptors are more sensitiev and accurate than central chemoreceptors.
False. Other way around.
T or F. CO2 crosses the blood-brain barrier easily.
True
Why is there a lot of CA in the cerebrospinal fluid (CSF)?
converts CO2 to HCO3- after in crosses the blood-brain barrier
What are the most important controls of breathing?
central chemoreceptors
Does activation of chemoreceptors increase or decrease ventilation?
increase
T or F. A decrease in PO2, a decrease in pH and an increase in PCO2 activates the peripheral chemoreceptors.
True
Describe the A band.
entire myosin bundle + overlapping regions of actin
Describe the I band.
regions of actin that do not overlap myosin
Describe the H zone.
area of sarcomere between opposing ends of of myosin
What are Z and M lines?
Z lines: anchor actin; M lines: where myosin filaments join
Why are actin's myosin-binding sites inactive when a muscle cell is at rest?
tropomyosin covers the binding sites
T or F. Ca2+ binds to tropomyosin.
False. Binds to troponin.
T or F. Troponin is bound to tropomyosin.
True
What happens when Ca2+ binds to troponin?
conformational change in troponin complex, tropomyosin shifts, myosin-binding sites exposed
What are the 5 steps of the crossbridge cycle?
1. myosin binds to actin
2. power stroke (Pi and ADP released, head pivots, actin pulled)
3. Rigor (low energy form, myosin and actin tightly bound, cycle stuck due to lack of ATP)
4. Unbinding of myosin and actin
5. cocking of the myosin head
An AP travels down _____ and causes a conformational change in _______________, opening _______ and causing ____ to be released.
T-tubules; DHP receptors; ryanodine receptors; Ca2+