Physiology Exam Questions

central dogma of molecular biology

DNA
transcription
mRNA transcript
translation
protein

amino acid derivatives

binding to its receptor sometimes produces a slow response and sometimes a fast response

central dogma of molecular biology

DNA
transcription
mRNA transcript
translation
protein

amino acid derivatives

binding to its receptor sometimes produces a slow response and sometimes a fast response

steroids

binding to its receptor almost always produces a slow response

peptides

binding to its receptor produces a fast response

Which of the four organic biomolecules is pictured here?

nucleic acid

Which of the following hormones would bind with a receptor inside the cell?

steriods

paracrine signals

Paracrine signals communicate with adjacent cells.
Autocrine signals are often also paracrine signals.

The role of oxygen in cells is to?

act as an electron acceptor

enzymes

metabolic catalysts
lower activation energy
proteins

What is the extracellular matrix of blood called?

Plasma

Which of the four major classes of organic biomolecules has up to three different folded structures?

proteins

When a catecholamine or peptide hormone binds to receptors on the surface of a cell…

second messengers are activated

What catabolic pathways in the body produce ATP?

glycolysis (2 ATP), citric acid cycle (2 ATP), and the electron transport chain (26-28 ATP)

Which of the following glial cells is found in the peripheral nervous system?

Schwann cells

The conduction of an action potential along an axon…

is not faster for a strong stimulus than a weak stimulus
is not faster along unmyelinated nerve fibers
does not decrease in amplitude as it is propagated along the axon

If GABA binds receptors on a post-synaptic cell body, what will likely happen to the membrane potential?

hyperpolarization

Where are synapses primarily located?

in grey matter

Which is least likely to diffuse across the blood brain barrier?

lipophobic molecule

If fluid taken from a lumbar puncture is not clear and colorless, this could indicate:

either an infection or a brain hemorrhage depending on the color

Which component(s) of the central nervous system is/are responsible for the basic functions of life (e.g., involuntary breathing and heart rate, relaying of sensory and motor signals)?

brain stem
spinal cord

dorsal root and horns

receive afferent signals

ventral root and horns

project efferent signals

parasympathetic division

dominates during the "resting and digesting" time and its ganglia are on or near the target organs

"dual innervation"

organ receiving both sympathetic and parasympathetic nerves

Imagine a scenario where a presynaptic neuron's voltage-gated Ca+ channels failed to open in response to the neuron's depolarization. Which of the following would result from this situation?

neurotransmitter would not bind to the receptors on the the postsynaptic neuron

protection of the brain

cranium
dura matter
subarachnoid space
cerebrospinal fluid (CSF)

During the rising phase of the action potential…

Na+ moves down both a concentration and electrical gradient.

A presynaptic neuron releases excitatory neurotransmitter into the synaptic cleft twice in a span of milliseconds. The resulting graded potential in the postsynaptic neuron reaches threshold and fires an action potential. This is an example of?

temporal summation

During a dissection, you observe a motor neuron that exits the spinal column at the level of thoracic vertebrae #3. It reaches its autonomic ganglion almost immediately upon exiting the spinal column. This must be a:

sympathetic pathway

central nervous system

brain and spinal cord

myelin sheath

does not cover the entirety of the axon
increases the speed of an action potential
composed of neuroglial cells

A neuron releases acetylcholine into the synaptic cleft at its target tissue. The acetylcholine binds muscarinic receptors initiating a response in the target tissue. Which autonomic pathway is this?

parasympathetic

secondary endocrine disorder

too much or too little hormone form the anterior pituitary

Considering a neuron with excitatory post-synaptic potential, you would predict that a drug binding and inactivating the breakdown enzyme for its neurotransmitter would result in…

more post-synaptic action potentials

Which statement accurately describes why a graded potential loses amplitude as it moves away from its stimulus?

Charged ions leak out of the membrane before reaching the trigger zone.

The nervous system's ability to communicate is primarily dependent on the movement of…

charged particles

blood-brain barrier

can be comprised of tight junctions between endothelial cells
permeable to small, nonpolar, or lipophilic molecules
helps protect the brain from pathogens

Successful recovery from a brain injury, like that seen in the case of Phineas Gage, likely requires the re-wiring of neuronal connections and possibly even the formation of new neurons. This type of reorganization is called…

neural plasticity

In a complex endocrine pathway, long-loop negative feedback inhibits…

the hypothalamus and/or the pituitary

During sexual intercourse, secretion and lubrication of the vagina is accomplished via parasympathetic innervation to the uterus, while contraction of the uterus (and/or vagina) is accomplished via sympathetic innervation. Similar to the male orgasm, these are best described as _.

synergistic (or cooperative) effects

If the white matter of the spinal cord is damaged, what symptoms would you expect?

impaired sensory relay
impaired movement

How does electroencephalography (EEG) detect brain activity?

free electrons in the metal electrodes respond to the flow of ions in and out of neurons

The brain is mostly composed of…

Which is used for rapid signaling over long distances?

action potentials

neurotransmitters that hyperpolarizes the cell will…

decrease the probability that the cell will produce an action potential
makes the cell body more negative

In order for an action potential to be propagated, the threshold membrane potential in the cell body must be reached…

once, at the axon hillock

somatosensory cortex

processes general sensory information and the size of the area dedicated to each part of the body is correlated with receptor concentraction

sodium-potassium (NaK) pump

uses active transport
binding of potassium (K+) triggers the pump to change shape
when the pump is open to the intracellular fluid its shape proves binding sites for sodium (Na+)

A neuronal pathway emerging from the cranial region that slows the heart rate must be a…

parasympathetic pathway

Neurotransmitter is stored and released from…

axon terminals

agonistic effects on the primary endocrine gland will…

increase production of the primary hormone
decrease production of releasing hormone from the hypothalamus
decrease production of tropic hormone from the anterior pituitary

afferent neurons

transmits information coming into the central nervous system

Both the cell body and the axon have Na+ channels. Are these channels the same or different? If so, how?

different, cell body has chemically-gated channels and axon has voltage-gated channels

action potential sequence

1. Na-K pump establishes resting membrane potential
2. stimulus causes a graded potential
3. graded potential reaches threshold at the axon hillock
4. voltage gated Na channels open near the axon hillock
5. additional voltage-gated Na channels open along the axon
6. Na-K pump re-establishes resting membrane potential

Which of the following is secreted by neurons AND acts via diffusion across a synapse?

neurotransmitters

What is the primary event causing the voltage change indicated by #4 on this image?

opening of voltage-gated sodium channels

What is located in the medulla oblongata?

centers for respiratory control (breathing)
pyramids, where tracts cross to the opposite side of the body
centers for vomiting control

Which neurocrine behaves as a neurohormone in the PNS and as a neurotransmitter in the CNS?

epinephrine

peripheral nervous system (PNS)

consists of all sensory and motor neurons outside of the CNS
contains components of the autonomic and somatic nervous system

limbic system

center for emotions

spatial summation

can be excitatory or inhibitory

The total amount of neurotransmitter released at the axon terminal is directly related to the…

total number of action potentials

charge distribution across a neuron's membrane

extracellular fluid = positive
intraceullar fluid = negative

Which of the following is true about efferent information in the central nervous system?

can be carried from the CNS by motor neurons

A person with defective rods will have trouble…

distinguishing shapes at the periphery of the visual field
seeing well in the dark

A blind spot in the retina occurs where…

the optic nerve leaves the eye

iris

controls diameter of the pupil

rhodopsin

light receptor

tectorial membrane

stimulates hair cells

cristae in ampullae

senses rotational movement

otoliths in maculae

senses lateral movement

The primary purpose of the middle ear bony structures (maleus, incus and stapes) is to…

amplify the vibration as it conducts to cochlea

You work at the Tabasco factory in Louisiana. You spend your workday blending barrels of fermented chili peppers with vinegar and bottling hot sauce. The smells do not bother you, because…

Olfactory receptors are phasic, they quickly adapt to constant stimulus.

skeletal muscle contraction

starts when the muscle fiber depolarizes due to the release of calcium into the cytoplasm

Why does rigor mortis occur after death?

myosin is tightly bound to actin
there is no ATP available to bind to myosin

Which is a potential energy source for an athlete sprinting the 40-yard dash?

phosphocreatine

smooth muscle contraction

Ca2+ initiates the contraction
uses actin-myosin crossbridges to create force
contraction can occur without a change in membrane potential

As a protective mechanism, stretching a skeletal muscle fiber causes sensory neurons (i.e. proprioceptors) to their rate of firing.

increase

troponin and tropomyosin in skeletal muscle contraction

they inhibit the bindings necessary for contraction

Most reflex movements are integrated by…

the spinal cord

Which is a characteristic of slow-twitch oxidative skeletal muscle fibers?

long contraction duration AND many mitochondria

Stretching a muscle spindle causes…

reflex contraction of that muscle.

Which of the following represents a somatic motor pathway?

Figure A

In the human eye, if the focuses the light anywhere but the then vision is imperfect.

lens, fovea

Bob fell off a ladder trying to clean out his gutters. His wife rushed him to the emergency room. The doctor tested his knee-jerk reflex and found it was normal. These results suggest that?

Bob has no damage to his spinal cord.

A person with defective rods will have trouble…

distinguishing shapes at the periphery of the visual field
seeing well in the dark

If you were floating in outer space experiencing zero gravity, the weightlessness would cause the otoliths in your macula to lose their reference point. Which of these sensations might you expect to have difficulty perceiving?

head position
linear acceleration

The neurons of the special senses each carry information to cortexes in the brain that are specific to each sense. However, general sensation information is all carried to the…

somatosensory cortex

In smooth muscle, the Ca2+ necessary for contraction can come from… 

the sarcoplasmic reticulum
the extracellular fluid

feedforward control

allows the body to anticipate a stimulus and begin a movement

negative feedback

generally result in the cessation of that movement

If glutamate is normally an excitatory neurotransmitter, why are some bipolar cells turned ON by light and some OFF by light?

different receptors

chemoreceptor

surcrose solution

mechanoreceptor

muscle tension

thermoreceptor

temperature

Sweet, bitter, and umami signals are communicated through a G-protein coupled which can amplify the signal sent to the primary sensory neuron.

second-messenger system

After an injury, Jodie has difficulty recognizing and interpreting certain sounds. These symptoms imply damage to the…

auditory cortex

During crossbridge cycling, the binding of ATP to the myosin head…

releases the myosin head from actin

M line

C

Z line

A