A neuron that has received an excitatory post synaptic potential (EPSP) is proba

Question

A neuron that has received an excitatory post synaptic potential (EPSP) is probably slight more _____than its resting state.
A.   Polarized
B.   Depolarized
C.   Short
D.   Long
E.   Ca++ infused

Which of the following brainstem nuclei are involved in exciting most brain neurons in order for them to be more ready to respond?
A.   Substantia nigra
B.   Periaqueductal gray
C.   The pyramids
D.   Olivary nuclei
E.   Reticular formation

Muscular contraction is impossible if ________ is/are not available.
A.   ATP
B.   Ca++
C.   Cl-
D.   ATP and Ca++
E.   ATP, Ca++, and Cl-

Of the three types of muscle fibers which generates the most force, all other things being equal?
A.   I
B.   IIa
C.   IIx

A muscle twitch occurs in response to an action potential (AP). Which of the following is not part of the description of a typical twitch?
A.   Speed period
B.   Latent period
C.   Contraction
D.   Relaxation

The accumulation of _____ in a muscle cell could lead to its fatigue (an inability to generate same or higher force as in prior attempts).
A.   Lactate
B.   H+
C.   ADP
D.   Pi
E.   A, B, C, and D
More force can be generated by muscle by ______.
A.   Recruiting more fibers/cells
B.   Recruiting larger fibers
C.   Developing more frequent Aps
D.   Recruiting more fast twitch fibers
E.   A-D are all involved in generating more force
Which of the chambers of the heart generates the most force/pressure?
A.   Right atrium
B.   Right ventricle
C.   Left atrium
D.   Left ventricle
E.   They all generate the same amount of force
Which of the following is a typical concentration of the three main gasses in our atmosphere at 22 degree C, 760 mmHg, and water content removed?
A.   N=~21%, O2= ~79%, CO2=~0.03%
B.   N=~79%, O2= ~21%, CO2=~0.03%
C.   N=~50%, O2= ~47%, CO2=~3%
D.   N=~40%, O2= ~50%, CO2=~10%
E.   N=~69%, O2= ~31%, CO2=~0.03%

Which of the following contribute to increased arterial blood pressure?
A.   Increased blood volume
B.   Increased CO
C.   Increased TPR
D.   Increased Blood Viscosity
E.   A-D, all contribute

Heart rate (HR) is increased by ______ of the heart, especially the sino-atrial node.
A.   Decreasing SNS innervation
B.   Decreasing PNS innervation
C.   Increasing SNS innervation
D.   Increasing PNS innervation
E.   Both B and C
As exercise intensity increases and HR increases, the time in both systole and diastole are ______. That said, _________ is affected the most when compared to rest.
A.   Increased; systole
B.   Increased; diastole
C.   Decreased; systole
D.   Decreased; diastole
E.   What; what?

Explanation / Answer

- A neuron that has received an excitatory postsynaptic potential (EPSP) is probably slightly more depolarized than its resting state.

B. Depolarized

The resting potential of a neuron is -70 mV. During an EPSP, there are ion channels opening resulting in a net positive charge across the membrane. This is known as delpolarization of the membrane where the neurons potential comes closer to the firing threshold of -55mV.

-Which of the following brainstem nuclei are involved in exciting most brain neurons in order for them to be more ready to respond?

E. Reticular formation

-Muscular contraction is impossible if ________ is/are not available.

D. ATP and Ca++

The contraction of a muscle fiber occurs as follows: The motor neuron innervating the muscle fiber sends a signal in the form of the neurotransmitter Acetylcholine. The membrane of the fiber depolarizes as positively charged sodium ions enter, triggering an action potential in the sarcolemma which then spreads to the T-tubules as well. This results in the release of stored calcium ions (Ca++) in the sarcoplasmic reticulum. The Ca++ then initiates contraction in the muscle fiber with the help of ATP.

-Of the three types of muscle fibers which generates the most force, all other things being equal?
C.   IIx

Type I muscle fibers produces low force, type IIx fibers generates high force while type IIa fall in between the two.

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