Physio Lec Practice Exam 2

Which of the following is NOW part of hemotasis?

Increased blood flow to the area

Which of the following statements about platelets is NOT correct

Platelets release Fibrinogen once a platelets plug is formed

Since fibrinogen is always present in the blood but the blood clot does not clot _____ must be absent unless a clot is needed

Thrombin

Plasmin:

Disposes of Fibrin

Heparin interferes with the actions of thrombin. Therefore which of the following would be seen if heparin is present?

There would be less fibrinogen activation

Studies have shown that high doses of aspirin decrease the formation of prostacyclin. Based on this information, what would be the effect of taking high doses of aspirin

More platelet aggression, so more blood clots

An increase in extracellular K+ concentration above normal, would lead to:

An Increase in Intracellular K+

If the membrane is only permeable to Cl- ions, the membrane potential will become positive: True or false?

This is true

If the membrane is only permeable to sodium, then at equilibrium the concentration of sodium ions will be equal on both sides of the membrane: True or false

False, at equilibrium, the electrical and chemical gradients balance each other. The concentrations don’t have to be equal

The Nernst equation is most often used to estimate the cell’s

The equilibrium potential for a specific ion; It calculates the voltage as which the electrical and concentration forces on one ion are balanced

If the concentration of Magnesium ions outside the cell is 1.2 mEq/l, and the concentration of magnesium ions inside the cell is 59mEq?l, what would be the equilibrium potential for magnesium?

-51 MV

If sodium were at equilibrium across the cell membrane, what direction would the electrical gradient move sodium?

Out of the cell; Sodium’s concentration gradient pushes it inward, so the electrical gradient must pull it outward to balance the forces

The membrane is more permeable to K+ than to Na+

At rest; Many K+ leak channels are ope, making the membrane more permeable to K+ than Na+

Multiple Sclerosis is associated with:

Destruction of myelin; it damages myelin in the CNS, slowing or interrupting nerve impulse conduction

If you could disable the inactivation of Na+ channels so that the channels remain open, what would happen to a neuron’s membrane potential?

It would depolarize more than normal during the action potential; Na+ would continue entering the neuron causing prolonged and excessive depolarization

Which of the following is NOT true of the absolute refractory period?

It does not end until K+ - Na+ pump has restored the ions to their original locations; The Absolute refractory period ends when sodium channels reset

As the strength of a depolarizing stimulus to an axon is continually increased:

The frequency of action potentials production will increase; Action potential size doesn’t increase bcs it’s all or none. Stronger stimulus will produce action potentials more frequently

The fact that X and Y both synapse with the same neuron is an example of:

Convergence; occurs when several neurons send information to one neuron

When the pre-synaptic neuron X is stimulated, the post-synaptic membrane becomes slightly hyper polarized. What kind of synapse if involved here?

An inhibitory response; it makes the postsynaptic neuron less likely to produce an action potential bcs it’s hyper polarized

Given the pre-synaptic neuron X causes hyper polarization of the post-synaptic neuron X, What kind of permeability changes might have occurred in the post-synaptic neuron

Increased permeability to K+ but not to Na+; K+ leaving the cell makes the inside more negative, producing hyperpolarization

Assume that pre-synaptic neuron Y fires at the same time as pre-synaptic neuron X, and the post-synaptic potential is more hyper polarized than when neuron X fired alone. What has happened?

Spatial summation of post-synaptic potentials; Occurs when post-synaptic potentials from different presynaptic neurons combine at the same time

Which of the following would occur if an axon were experimentally stimulated at both ends

The action potentials stop when they meet in the middle; action potentials cannot pass through each other. When they collide, each encounters a refractory region and stops

When a membrane is stimulated such that chemically-gated monovalent cation channels open, which of the following always happens

A graded potential is established; opening these channels changes the membrane voltage locally. it may or may not fire an action potential

Which of the following statements concerning propagation potentials is TRUE:

Saltatory conduction occurs only In the myelinated fibers; in myelinated axons action potentials jump from one node of Ranvier to the next, increasing conduction speed.

In the depolarization phase of the action potential:

Sodium channels are closed and potassium channels are open; sodium entry stops, while potassium leaves the cell and makes the membrane potential more negative

A neuron is exposed to (TTX) and then is stimulated by an above-threshold stimulus. Is the following statement true or false?…

“A graded potential will occur in the dendrites and cell body, but an action potential will not be initiated in the axon.”

True; TTX blocks voltage gated Na+ channels. Graded potentials can still occur but the axon cannot generate an action potential

In an experiment on synapses, you bath a synapse in a medium which Is similar to extracellular except that it has no calcium. What is the expected result?

Less neurotransmitter will be released from the presynaptic cell; Ca+ entering the presynaptic terminal is required for synaptic vesicles to release neurotransmitters

Which of the following is NOT a function of astrocytes?

Defending the CNS against infections; microglia are the immune defense cells of the CNS.Astrocytes support neurons and help maintain the blood brain barrier

Which of the following is NOT primarily neuron cells bodies and dendrites?

Corpus callousm; it contains mostly myelinated axons connecting the two cerebral hemispheres

Which of the following statements about meninges is TRUE?

The meninges surround both the brain and the spinal cord; The dura mater, arachnoid, and Pia matter protect and surround the CNS

Cerebra spina fluid:

Acts as shock absorber; it cushions the brain and spinal cord and helps protect them from physical injury

Which type of glial cell specifically lines the ventricles of the brain?

Ependymal cells; and are involved in producing and circulating cerebrospinal fluid

Which part of the Braine transmits and integrates sensory information between the lower CNS and the cerebral cortex

Thalamus; serves as a major relay station for sensory information going to the cerebral cortex

Which part of the brain is the direct link between the nervous system and the endocrine system?

Hypothalamus; it controls the pituitary gland and connects nervous system activity with hormone secretion

When this portion of the brain is affected by alcohol, it results in a lack of balance and coordination:

Cerebellum; it coordinates movement, balance, posture, and motor precision

The corpus callous connects the:

The two hemispheres of the cerebrum; it allows communication between the left and right cerebral hemispheres

Which structures does NOT have some role in skeletal muscle control?

Hypothalamus; it regulates homeostasis and endocrine function

Parkinson’s disease is caused by a deficiency of:

Dopamine; causing problems with movement control

A patient suffers a stroke and as a result has reduced sensitivity in the skin on the left arm. Which part of the cerebral cortex appears to be damaged?

Right parietal lobe; it receives sensory information from the left side of the body. The parietal lobe processes body sensations

Which of the following is a monosynaptic reflex?

Stretch reflex; Uses one synapse between a sensory neuron and a motor neuron allowing a rapid response

Which cranial nerve primarily innervates organs in the thoracic and abdominal cavities?

Vagus Nerve; the vagus nerve carries parasympathetic signals to many organs in the chest and abdomen

Which part of the spinal cord contains the cell bodies of the interneurons with which sensory neurons synapses?

Dorsal horn; Sensory neurons enter the spinal cord through the dorsal root and synapse with interneurons in the dorsal horn

Which of the following is most likely to happen if the ventral root on the right side of the cord is served?

Loss of movement on the right side of the body supplied by that nerve; ventral roots contain motor fibers. Damage causes motor loss on the same side

Which of the following are NOT in a spinal nerve?

all are in the spinal cord; Spinal nerves contain sensory and motor fibers, myelinated and unmyelinated fibers, fibers of different diameters, and Schwann cells.

Which neurotransmitter is released in the sympathetic ganglion chain?

Acetylcholine; sympathetic preganglionic neurons release acetylcholine onto nicotinic receptors in the autonomic ganglia

Parasympathetic preganglionic fibers

Are cholinergic; cholinergic neurons release ACh, parasympathetic preganglionic neurons release ACh in the automatic ganglia

Which type of autonomic receptor is found in the synapse of the parasympathetic preganglionic fiber with the effector organ?

muscarinic receptor; parasympathetic postganglionic neurons release ACh, which binds to muscarinic receptors on target organs

Which is a sympathetic response?

The pupils of the eye dilate; sympathetic activity prepares the body for action by dilating the pupils, increasing heart rate and redirecting blood flow

Terbutaline is a beta 2 agonist. Which of the following would be and effect on taking this drug?

Vasodilation; Beta-2 receptor stimulation relaxes smooth muscle in certain blood vessels causing vasodilation

autonomic neurons are this type of neuron:

Efferent neurons; autonomic neurons carry motor commands from the CNS to smooth muscle, cardiac muscle, and glands