Physiology Exam 2 Flashcards
What about veins allows them to accommodate high volumes with little change in pressure.
Large Compliance
What is Venous return?
Venous return is the volume of blood returning to the central venous compartment (i.e., thoracic venae cavae and right atrium) per minute.
What promoted Venous return? High or Low CVP?
Low CVP promotes venous return into the central venous compartment.
What inhibits Venous return? High or Low CVP?
High CVP inhibits venous return into the central venous compartment.
If a 20-year-old and a 60-year-old male had the same body mass, cardiac output, heart rate, and mean arterial pressure, which of the following would characterize the circulatory system in the 60year-old as compared to that in the 20-year-old?
A. The 60-year-old man would have a lower systolic pressure.
B. The 60-year-old man would have a higher diastolic pressure.
C. The 60-year-old man would have a higher cardiac workload.
D. The 60-year-old man has elevated arterial resistance.
C. The 60-year-old man would have a higher cardiac workload.
Which of the following will be seen when both heart rate and stroke volume are increased? A. Increased mean arterial pressure B. Increased central venous pressure C. Increased pulse pressure D. Decreased diastolic pressure
C. Increased pulse pressure
Which of the following is true of the relationship between cardiac output (CO) and central venous pressure (CVP)?
A. Increased CVP increases CO
B. Equal CO to CVP results in increased flow (L/min)
C. Increased CO increases CVP
D. Decreased CVP increases CO
D. Decreased CVP increases CO
Autoregulation of blood flow in organs such as the heart and brain allows:
A. changes in arterial pressure to cause proportional changes in organ blood flow.
B. their oxygen supply to remain stable in spite of fluctuations in arterial pressure.
C. constriction of their arterioles when arterial pressure decreases.
D. neurogenic reflexes to control vascular resistance in those organs.
B. their oxygen supply to remain stable in spite of fluctuations in arterial pressure.
If blood flow to an organ is 100 mL/minute when the mean arterial pressure in the main artery supplying the organ is 100 mm Hg, which of the following flow conditions is inconsistent with the properties of autoregulation of blood flow when the mean arterial pressure in the supplying artery is reduced to 80 mm Hg? (For this question, do not consider any effects of activation of blood pressure reflexes in the response.) A. Blood flow = 75 mL/minute B. Blood flow = 85 mL/minute C. Blood flow = 90 mL/minute D. Blood flow = 99 mL/minute
A. Blood flow = 75 mL/minute
If mean capillary hydrostatic pressure = 30 mm Hg, interstitial hydrostatic pressure = 0 mm Hg, plasma oncotic pressure = 25 mm Hg, and interstitial oncotic pressure = 2 mm Hg, which of the following will create a situation in the capillary where there is no net reabsorption or filtration of fluid across the capillary?
A. Reducing plasma oncotic pressure to 22 mm Hg
B. Decreasing interstitial oncotic pressure to –4 mm Hg
C. Increasing interstitial hydrostatic pressure to 7 mm Hg
D. Increasing plasma oncotic pressure to 30 mm Hg
C. Increasing interstitial hydrostatic pressure to 7 mm Hg
What will occur in a person with intact cardiovascular neural reflexes when a sudden drop in mean arterial pressure from a normal value of 95 mm Hg to 70 mm Hg?
A. Constriction of cutaneous arterioles
B. Maximized carotid baroreceptor nerve firing rate
C. Contraction of cerebral arteries
D. Stimulation of the vasodepressor center in the medulla
A. Constriction of cutaneous arterioles
Heart rate is \_\_\_\_\_\_\_\_\_ in response to \_\_\_\_\_\_\_ firing rate of arterial baroreceptor nerves. A. increased; increased B. decreased; decreased C. increased; decreased D. decreased; zero
C. increased; decreased
If an individual’s resting heart rate is 75 beats/minute (bpm), complete blockade of the parasympathetic and sympathetic nerve activity to the heart will result in which of the following heart rates?
A. >75 bpm because of elimination of sympathetic activity to the heart
B. < 75 bpm because the parasympathetic nerves dominate heart rate at rest
C. >75 bpm because sympathetic nerves dominate heart rate at rest
D. >75 bpm because acetylcholine hyperpolarizes the SA node
D. >75 bpm because acetylcholine hyperpolarizes the SA node
What are receptors specific for?
Specific for stimulus
What is a slow adapting receptor also known as?
Tonic
what is a fast adapting receptor also known as?
Phasic
What are the 4 cutaneous sensory modalities?
Pain, Touch, Vibration, Temp
Final destination of the somatosensory system?
Post central Gyrus in the parietal lobe
Talk about Ruffinis’s endings
Contribute to the sensation of touch Have large receptor fields Slow adapting Skin stretch Slightly deeper than meissners and merkles but more superficial than pacianian
Talk about Pacinian corpuscles
Very rapidly adapting
Rapidly changing stimuli
VIbration
Deepest
Talk about Merkle’s Discs
Small receptor fields These allow for fine discrimination Slow adapting Detect steady pressure Most superficial
Talk about Meissner’s corpuscles
Small receptor fields These allow for fine discrimination Fast adapting Detect rapid changes Most superficial
What is the area of the skin supplied with afferent nerve fibers called?
Dermatomes
Talk about hair follicles
These have a nerve plexus that senses hair displacement.
Describe somatosensory system
- Final destination is Post central gyrus in parietal lobe
- It is the sensory network that monitors the surface of the body and conveys sensations from the skin and muscles.
- Has 4 cutaneous modalities (pain, touch, vibration, temp)
- Includes proprioception, this relates sensory info to the musculoskeletal system.
Name 3 types of receptor adaptation
(constant stimulus applied to all 3)
no adaptation = generator potential and action potential are constant and unchanged
fast adaptation
slow adaptation
Describe no receptor adaptation
no adaptation
There is constant action potential
(with constant stimulus applied)
no adaptation = generator potential and action potential are constant and unchanged
Describe slow receptor adaptation
Slow receptor adaptation
There is a slow gradual decline in action potential
(example is application of pressure)
(with constant stimulus applied)
slow receptor adaptation respond to constant stimuli with a gradual decline in the generator potential and the action potential frequency
Describe Fast receptor adaptation
Fast adapting receptor
There is a rapid decline in the action potential
(example is tension on a working muscle)
(with constant stimulus applied)
Fast adapting receptors have a generating and action potential that declines rapidly in response to a constant stimulus
Tonic adapting
The frequency of the action potential slowly decreases, but there is a relatively constant input of information. This means that there is a steady stimulus but that you are aware of the stimulus constantly.
Phasic Adapting
The frequency of the action potential rapidly drops off, you adapt to the stimulus. this can happen with some of the touch receptors or smell receptors. (you initially smell something but soon the smell doesn’t leave, you just stop noticing it.)
What is receptor adaptation
The decline in action potential generating when a constant stimulus is applied.
It is necessary so that constant environmental stimuli can be ignored preventing a flood of input info to the CNS.
The generator potential declines over time with constant stimulus.
Corpuscle
A nerve ending packaged in a bulb
The term hematocrit refers to:
A. The percentage of total blood volume that is plasma. This is normally about 45%
B. The percentage of total blood volume that is WBC. This is normally about 45%
C. The percentage of total blood volume that is RBC. This is normally about 55%
D. The percentage of total blood volume that is RBC. This is normally about 45%
D. The percentage of total blood volume that is RBC. This is normally about 45%
Which of the following cells are agranulocytes? A. Eosinophils B. Lymphocytes C. Neutrophils D. Polymorphonuclear leukocytes
B. Lymphocytes
A person with type A blood can safely donate RBCs to someone of type \_\_\_\_\_\_\_\_\_\_ and can receive RBCs from someone of type \_\_\_\_\_\_\_\_\_\_. A. O; AB B. AB; O C. A; B D. B; A
B. AB; O
Polycythemia vera is a hereditary neoplastic bone marrow disorder characterized by abnormally high red blood cell production. The steady state concentration of a substance in serum can provide additional information to confirm the diagnosis of the patient with polycythemia vera. Its level is typically low. This is in contrast to patients with secondary polycythemia, which is caused by respiratory conditions like emphysema that stimulate erythrocyte production. Which of the following substances is most likely tested? A. Albumin B. Bilirubin C. Erythropoietin D. Plasmin
C. Erythropoietin
John has AB negative blood. Which blood types can receive John’s blood? A. A negative B. B negative C. AB positive D. O negative
C. AB positive
An individual is diagnosed with myopia. Which lens will correct this visual defect? A. Flat B. Cylindrical C. Concave D. Convex
C. Concave
Where is the second-order neuron of somatosensory input located? A. Pons B. Medulla oblongata C. White mater of spinal cord D. Thalamus
B. Medulla oblongata
“old man eyes” is due to? A. distortion of the cornea B. loss of receptor cells in the foveal region of the retina C. shortening of the eyeball D. changes in the elasticity of the lens
D. changes in the elasticity of the lens
Which of the following vessels has the greatest compliance? A. Arteries B. Arterioles C. Capillaries D. Veins
D. Veins
All arteries and veins are innervated by postganglionic branches of the sympathetic nervous system. These nerves release norepinephrine onto the smooth muscle of veins and arteries causing these vessels to contract. The vascular effects of a generalized activation of the sympathetic nervous system would therefore be predicted to
A. Decrease venous compliance and decrease arterial flow resistance.
B. Increase venous compliance and increase arterial flow resistance.
C. Increase venous compliance and decrease arterial flow resistance.
D. Decrease venous compliance and increase arterial flow resistance.
D. Decrease venous compliance and increase arterial flow resistance.
Which of the following will exacerbate the pooling of blood that occurs in veins in the lower extremities of a patient when he or she assumes an upright position?
A. Activation of α-adrenergic receptors on veins by the sympathetic nervous system
B. Administration of the antianginal drug, nitroglycerin, which directly dilates veins more than arteries*
C. Administration of the emergency antihypertensive agent sodium nitroprusside, which directly dilates arteries more than veins
D. Placing the patient in supine position with his or her legs up
B. Administration of the antianginal drug, nitroglycerin, which directly dilates veins more than arteries
Which of the following is the result of an inward Na+ current?
A. Upstroke of the action potential in the sinoatrial (SA) node
B. Upstroke of the action potential in Purkinje fibers
C. Plateau of the action potential in ventricular muscle
D. Repolarization of the action potential in ventricular muscle
B. Upstroke of the action potential in Purkinje fibers
Which phase of the ventricular action potential coincides with diastole? A. Phase 1 B. Phase 2 C. Phase 3 D. Phase 4
D. Phase 4
During which phase of the ventricular action potential is the influx of Ca2+ highest? A. Phase 0 B. Phase 1 C. Phase 2 D. Phase 3
C. Phase 2
During which phase of the cardiac cycle does the mitral valve open?
A. Isovolumetric ventricular contraction
B. Rapid ventricular ejection
C. Isovolumetric ventricular relaxation
D. Rapid ventricular filling
D. Rapid ventricular filling
Cardiac output of the right side of the heart is what percentage of the cardiac output of the left side of the heart? A. 25% B. 50% C. 75% D. 100%
D. 100%
An increase in contractility will directly result in a decrease in which of the following? A. cardiac output B. end-systolic volume C. end-diastolic volume D. stroke volume
B. end-systolic volume
How many “order” neuron is somatosensory pathway?
It is a third order neuron pathway (3 neurons) but is sometimes considered a fourth order neuron if you count the relay from the post central gyrus to the association area where the information is interpreted.
The first order neuron of the somatosensory pathway?
Receptor neuron Goes from receptor to dorsal column Is an afferent (in) neuron It is located in the peripheral spinal nerve Axons ascends the white matter
The second order neuron of the somatosensory pathway?
Located in the dorsal column nuclei of the caudal medulla
The axon decussates (crosses over)
It ascends through the brainstem to the thalamus
It travels the medial lemniscus tract
The third order neuron of the somatosensory pathway?
Located in the thalamus
ascends to the primary somatosensory cortex
Travels via the white matter of the internal capsule
What is the site of decussation in somatosensory system?
Second order neuron
At level of medulla
Damage below decussation results in ipsilateral loss
Damage above decussation results in contralateral loss
What is the major somatosensory tract?
DCML
dorsal medial lemniscus tract
What is the main pathway for temperature or pain?
3 order neurons
glutamate or substance P is released by the first order neuron in afferent pain pathway
What is pain gating?
When non painful sensory stimulation is simultaneously applied (gentle rubbing)
Touch fibers enter the same dorsal root as the pain fiber send a collateral signal that synapses on inhibitory interneurons within the grey matter
This causes a release of opioids and inhibits transmission of pain in first and second order neurons
It basically confuses the brain with multiple signal and multiple inputs.
What is convergence projection?
This theory explains referred pain
Nerves share the same entrance point in the spinal cord
The CNS misinterprets the source of the pain
What two descending pathways can stimulate enkephalinergic interneurons (opiods)
A serotonergic pathway from the raphe nucleus of medulla and the norepinephrinergic pathway from the locus ceruleus of Pons
What is 2 point discrimination test?
Distance and differentiation between two points
Best at lips and fingertips
Worst at calf and lower back
less cortical tissue devoted in lower regions an a lower density of receptors
High discrimination is due to many merkels and meissners corpuscles
Large number of neurons in pathway
more cortical tissue devoted
What is left side of brain for?
Logic speech Verbal memory hearing sounds rational thought
What is right side of brain for?
Artistic Shape memory Hearing non verbal sounds Musical Facial recognition
What is accommodation
The ability to change the optical power of the lens to maintain focus at various distances.
Goal is to get light rays to converge on fovea centralis
macula lutea = dartboard
fovea centralis = bullseye
What is presbyopia
Reduced accommodation due to decreased elasticity in lens
Occurs with age
What is convergence reflex?
Occurs when focusing on a near object
Has 3 components (3 C’s)
Convergence of eyes to maintain a single image
Constriction of pupils of circular muscle
Contraction of ciliary muscles
Reflex is mediated by parasympathetic nerve of the eyes
Cornea does majority of focusing, lens does very little
Myopia
Nearsightedness
Light is focused in front of retina
Need concave (skinny) lens to correct
Eyeball is too long
Hyperopia
Farsightedness
Light is focused behind retina
Need convex (fat) lens to correct
Eyeball is too short
Astigmatism
Incorrect curvature of the eye in one plane
two different focal distances are produced depending on which
Need cylindrical lenses to fix
What are rods for?
Black and white (grey)
Allows high sensitivity to light
Allows objects to be seen in low intensity light
What are cones for?
High intensity light
Color vision
Located mostly in fovea
High visual acuity due to one cone cell synapsing with single bipolar cell
The single bipolar cell then synapses with single ganglion cell
Blue, green red
Why is visual acuity lower at the periphery?
More rods are at the periphery
many rods converge on a single ganglion cell
Fovea centralis
High visual acuity due to one cone cell synapsing with single bipolar cell
Bipolar cell then synapses with ganglion cell
no rods here, only cones
color vision
Where is vision at highest resolution
Central vision is highest resolution
poor in dim light
Peripheral vision is low resolution but good in dim light
Details about color blindness
It is a common condition
x linked recessive (more often in men)
Could be from a range of defects
Most commonly from a missing cone type
Light through the cells in order
Light passes through all the cells until it hits the photoreceptors where it is collected
The signal then moves from the photo receptors (rods & cones) to the horizontal cell
Then to the bipolar cell
the amacrine cell
the ganglion cell
the optic nerve (CNII)
the Optic chiasm
what is the blind spot
The optic disc
we should see the blind spot but our brain fills in the gap for us
