Physiology test 2
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atropine applied to the eye blocks what chemical
what is the sensory nerve for smell
what reflex causes the knee jerk
What are the "Nodes of Ranvier"
the gaps formed by the myelin sheath.
In the parasympathetic nervous system the ganglionic fibers secrete what
acetylcholine at their terminal synapses.
is an excited neuron more positive or negative?
what does the adrenal medulla secrete after stimulation
norepinephrine and epinephrine
what occurs in an unexcited neuron and causes depolarization
what makes the pupil constrict
when light is directed into the eye
What happens to the iris when light is shown in the eye
What is ATP & what is its function
- adenosine triphosphate
- needed for muscle relaxtion
name the junction b/w axon knobs and dendrites of neurons at which inhibitory nerutransmitter substances are released
what is epideral ansthesia and what happens
the space outside the dura & injected into the epidural space decreases perception of pain by blocking nerve transmission.
where are respiration and the HR controlled
in the hindbrain region more specifically the pons
explain the relationship between the cranial nerve and the eye
the cranial nerve maintains equilibrium (hand-eye coordination), if the cerebellum is damaged then the eyes can follow it but the body cant pick it up.
what effect does the parasympathetic/sympathetic system have on the GI tract,heart, and eyes
- Gi tract motility-increase
- heart rate-decrease
- pupil size-constrict
- GI tract motility-decrease
- heart rate-increase
- pupil size-dialation
how does atropine produce dilation of the pupil
Atropine blocks the muscarinic receptors preventing acetylcholine from causing constriction of the pupil. Therefore the pupil stays dilated (wide open) for the eye exam.
describe fast twitch muscles
contain little myoglobin, the muscular form of hemoglobin, and rely largely on glycolytic processes for energy metabolism.
a nerve that conveys impulses toward or to muscles or glands
a nerve that passes impulses from receptors toward or to the central nervous system
which region of the brain is involved with automatic control or function?
the medulla oblongata (hindbrain)
what is the function of the motor component of the arc in a operation of a reflex
efferent nerve-to convey impulses toward muscles or glands
what is the eustachian tube?
it connects the middle ear with the nasopharynx and equalizes the pressure between the atmosphere and the middle ear.
what part of the brain coordinates movement?
sin and troponinwhat is tropomy
they are both regulatpry proteins and make up 2/3 of a actin protein.
describe actin and myosin
they are both contractile proteins , but actin makes up 1/3 of a actin filament.
describe sensory neuron
conducts nerve impulses through an afferent pathway toward the Central Nervous System (CNS)
describe a patellar reflex
Tapping the dog's patella ligament causes extension of the stifle. The stifle is equivalent to the human knee. Striking the patellar ligament stimulates stretch receptors (muscle spindles) in the quadriceps muscle; this information is transmitted to the spinal cord via afferent neurons. Afferent neurons communicate with interneurons, which communicate with efferent (motor) neurons. The nerve impulse will travel along the motor neuron back to the quadriceps muscle and cause it to contract. This contraction extends the stifle.
the opening of sodium channels on a neuron result in what action potential
sodium(Na+) rushes in making the cell more positive, therefore depolarization
what is the function of the sacroplasmic reticulum
a network of tubules within the sarcoplasm that is important for the excitation-contraction process
where does contraction-relaxtion occur
what is the function of the Transverse tubules
transmit action potentials from the sarcolemma into the interior of the cell to initiate contraction of the myofibril.
what happens to the sacromere length during muscle contraction
what degrades acetylcholine after it binds to its receptors on the sarcolemma of skeletal muscles
what happens when a substance like curare binds to acetylchaline receptors
Curare is not destroyed by acetylcholinesterase; therefore, acetylcholine cannot bind to its receptors, an action potential cannot be produced, and muscle contractions cannot occur. Death can result from asphyxiation because the muscles needed for breathing are unable to contract.
what effect does clostridum botulinum toxin have on muscles
no action potentials can be produced for muscle contraction; this can result in deadly paralysis
what effcts do organophosphates have on the neuromuscular junction and muscle contraction
they inhibit the action of acetylcholinesterase, causing the buildup of ACh and resulting in muscular spasm and asphyxiation
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