Physio Quiz & HW

The refractory period occurs when_______.

voltage-gated sodium channels are inactivated and potassium channels are open

A threshold stimulus immediately __________

opens voltage-gated sodium channels

In myelinated axons, an action potential occurs _________ and they propagate __________.

at nodes of Ranvier; rapidly

Concentration gradients exist across the plasma membrane., Specifically, there are ___________.

more potassium ions inside and more sodium ions outside of the plasma membrane

The value of the resting membrane potential is ___________.

-70 mV

The Na+/K+ pump transports ________.

Na+ out of and K+ into the cell

Neurons that lie entirely within the CNS are called ___________.

interneurons

Which of the following glial cells become part of the blood-brain barrier?

astrocytes

A neuron under the influence of a neurotransmitter that opens K+ channels will _____________ (two answers)

- be less likely to fire an action potential
- become hyperpolarized

Ouabain, a specific inhibitor of the Na+-K+ pump, is applied to a neuron. What effect will this have on the subsequent action potential fired by that neuron?

There will be no effect

During the repolarization of a neuron:

K+ moves from cell to ECF

Release of a neurotransmitter requires: (two answers)

- Ca2+ entry into the cell
- an action potential

Communication between neurons is not always one-to-one. When a group of presynaptic neurons provides input to a smaller number of post-synaptic neurons it is called:

convergence

What is the function of the cerebrospinal fluid? (three answers)

- the CSF provides a route by which wastes can be removed from the CNS
- the CSF provides protective padding for the brain
- the buoyancy of the CSF reduces the weight of the brain

The purpose of the blood-brain barrier is to

protect neurons from potentially harmful substances in the blood

The pyramids are a region within the medulla responsible for which of the following?

The fact that each side of the brain controls the opposite side of the body

What causes the depolarization phase of the action potential?

K+ exiting the cell through voltage-gated ion channels

During the rising phase of the action potential ______________.

sodium moves down both a concentration and electrical gradient.

Which of the following is TRUE about one of the two gates in NA+ channels in axons?

The closing of the inactivation gate stops the depolarizing during an action potential

If a neuron has receptors for a particular neurotransmitter it will

respond in a similar way to an agonist of that neurotransmitter

The ability of the nervous system to change activity at the synapse is called

synaptic plasticity

Neural tissue has a minimal extracellular matrix so support and protection come from external sources. Which of the following are involved in this support and protection? (four answers)

- cerebrospinal fluid
- the meninges
- glial cells
- outer casing of bone

Each of the following has lower concentrations in CSF compared with plasma EXCEPT:

a. Ca2+

b. Na+

c. K+

d. HCO3-

e. glucose;

Na+

Each of the following regarding the blood-brain barrier is true except:

gap junctions exist between endothelial cells of the capillaries → has tight junctions

Except in periods of starvation, the only fuel for the brain are __________ so 15% of blood pumped by the heart goes to the brain to supply enough __________ from which to generate ATP.

glucose - oxygen

Which of the following pairings is not correct?

Thalamus; relays and modifies information going to and from the cerebellum → thalamus responsible for relaying information from the senses to the cerebral cortex

Midbrain:

Relays signals & visual reflexes

Medulla Oblongata:

Contains control centers for BP & breathing

Hypothalmus:

hemostatsis

Cerebellum:

Mvmt & cordination

If you close your eyes and reach forward with one hand you will know the position of that hand because of ___________ activation.

proprioceptor

A two-point discrimination test allows for the differentiation between

receptive fields

Which of the following receptors fire rapidly when first activated, then slow and maintain their firing as long as the stimulus is present?

tonic receptors

The intensity of a sensory stimulus is coded by

the frequency of action potentials

A blow to the eye causes us to see a flash of light or "stars" even though the photoreceptor is not being activated by light. This can be explained by which of the following?

labeled line coding

Chemicals such as histamine, prostaglandins, serotonin, and substance P

only sensitive and activate nociceptors

Which of the following physiological responses results from sympathetic action? (three answers)

- increase heart rate
- dilation of blood vessels
- stimulation of glycogenolysis

The neurotransmitter norepinephrine is synthesized from

tyrosine

The receptor found on most parasympathetic target cells is

muscarinic cholinergic

The enzyme monoamine oxidase (MAO) breaks down

catecholamines

The synapse of a somatic motor neuron on a muscle fiber is called the

neuromuscular junction

When a skeletal muscle lengthens, its sarcomeres

lengthen

Which of the following characteristics differentiates skeletal muscle from both cardiac and smooth muscle? (two answers)

- multinucleated fibers
- movement is controlled by a somatic motor neuron

Why does rigor mortis occur after death?

myosin is tightly bound to actin

If you want to study smooth muscle, it doesn't matter what organ it comes from because all smooth muscle is alike.

False

Which of the following phases of a muscle twitch requires ATP? (two answers)

- contraction period
- relaxation period

In smooth muscle, the Ca2+ for contraction comes from: (two answers)

- extracellular fluid
- sarcoplasmic reticulum

Drug "X" inhibits acetylcholinesterase action within the neuromuscular junction. What would drug "X" do to the membrane potential of the muscle fiber?

it would remain depolarized

Which of the following is NOT true regarding the innervation of skeletal muscle?

multiple motor units innervating a skeletal muscle also contact all at once

The function of transverse tubules is to

rapidly conduct action potentials to the interior of the muscle fiber

Each myosin head has a binding site for

actin and ATP

The somatic motor neurons that innervate skeletal muscle fibers are called

alpha motor neurons

Spinal reflexes are to the spinal cord as cranial reflexes are to the

brain

Stretching the muscle spindle causes

reflex contraction of the muscle

Which of the following helps us to maintain body position as we move through space?

postural reflexes

Convergence describes

how multiple primary sensory neurons synapse on a single secondary neuron.

Visceral pain is poorly localized and can be perceived to originate from a region of the body that is different from its actual location; this is called

referred pain

Chronic pain is

only pathological

The gate control theory of pain modulation states that pain transmission can be blocked by:

mechanical stimulation of A-beta fibers

The vitreous chamber of the eye

helps to stabilize the structure of the eye and the retina

The presence of two peripheral efferent neurons in a pathway is typical of the __________ division

autonomic

The motor end plate is

a folded area of muscle cell membrane with ACh receptors clustered at the top of each fold

For antagonist's muscle groups to move a limb, flexor contraction occurs coincident with:

relaxation of the extensor

The contraction cycle is triggered by the rise in __________ released from the sarcoplasmic reticulum

Ca2+

A motor unit consists of

one neuron and all the skeletal muscle fibers it controls

Compared to skeletal muscle, the contraction of smooth muscle cells is

sustained without fatigue

Which of the following statements is true? (ALL ARE TRUE)

- cranial reflexes are integrated into the brain

- visceral reflexes are controlled by autonomic neurons

- reflex movements are integrated primarily into the spinal cord

- spinal reflexes do not require input from the brain

The _________ supply blood to the heart muscle itself

coronary arteries

The right ventricle pumps ________ blood into the ___________ circulation

deoxygenated; pulmonary

Which of the following is INCORRECT regarding diastole (filling of the heart)?

pressure in the ventricles is greater than in the atria

Which of the following are common mechanisms used to control blood flow to different areas of the body? (two answers)

- vasoconstriction of the blood vessels
- vasodilation of blood vessels

During the T wave, which of the following is true?

both ventricles are repolarizing

Plasma proteins decrease in a person with liver failure. What effect does this have on capillary filtration/absorption?

net filtration increases

The term for the production of blood cells is

hematopoiesis

The glycoprotein thrombopoietin (TPO) regulated the growth and maturation of

megakaryocytes

Calculate mean arterial pressure if a person has a blood pressure reading of 107/72

84 mm Hg

(T/F) Sympathetic output from the cardiovascular control center acting on b2-adrenergic receptors causes vasodilation in the heart and vasoconstriction in skeletal muscles

False

Which of these statements about the heart is false?

the action potential of a cardiac contractile cell is identical to that of a skeletal muscle cell

Which of the following is the SAME regarding the action potential of a neuron and of a myocardial contractile cell? (two answers)

- Na+ influx is responsible for the depolarization phase
- K+ efflux is responsible for the rapid depolarization phase

A withdrawal of parasympathetic nerve activity has which of the following effects?

increases heart rate

Blood flow through an arteriole _______ when it dilates

increases

If one arteriole constricts and nothing else changes, what will happen to mean arterial pressure?

it increases

Systemic arterioles ___________ in response to decreasing oxygen

dilate

Blood flow velocity is slowest in the

capillaries

Which of the following vessels undergo a change in diameter based on neural input? (two answers)

- arterioles
- veins

If blood pressure increases, the

net filtration across the capillary walls increases

Which of the following is/are correct for arteries but not veins?

store pressure generated by the heart

Local control of arteriolar resistance leads to an increase in blood flow to tissue when

H+ level increases

Which of the following is NOT a mechanism used by the lymphatic system to control the flow of lymph?

osmosis

Which blood elements are lacking a nucleus? (two answers)

- erythrocytes
- platelets

Which of the following is the major contributor to the fact that water gets pulled from the interstitial fluid into capillaries?

albumins

Normally, whole blood is composed of _____________% cells and ____________% plasma

40; 60

Which of the following does not promote platelet activation and/or aggregation?

prostacyclin

The end product of the coagulation cascade is

cross-linked fibrin

Antibiotic drugs act against

bacteria

The body's specific immune response is mediated by

antibodies

Which of the following chemicals stimulate pain receptors?

bradykinins

During a primary immune response; which antibody level is increased?

IgM

IgG

Secondary Immune Response
Can cross placenta
Responsible for resistance against viruses, bacteria, & bacterial toxins

IgA

External (grandular) Secretions