Lab Final Exam Unit 2 Flashcards
What are the two divisions of the Nervous system. Give their organs and functions.
- Central Nervous System - brain and spinal cord - controls body function
- Peripheral Nervous System - nerves and ganglia - communicates with the CNS from or to rest of the body.
Define Resting Membrane Potential. What is the resting membrane potential of a typical neuron?
The voltage (charge) differences across the cell membrane when the cell is at rest. -70mV
Define absolute refractory period.
the delay that happens after the first action potential has begun, before the second can be triggered; the time requred for the Na+ channel gates to reset to their resting positions (about 1-2 msec.)
Define relative refractory period.
follows the absolute refractory period. During this time some, but not all, Na+ channel gates have reset to their original positions and some K+ channels are still open.
What happens during depolarization?
Na+ enters the cell
What happens during repolarization?
K+ exits the cell
What type of channel does Na+ use to enter the cell? What causes it to open? close?
voltage gated na+ channel
opens at the threshold of -55mV; closes at +30mV due to an inactivation gate that inactivates the channel.
What type of channel does K+ use to exit the cell? What causes it to open?
voltage gated K+ channel
Slowly begins to open at the threshold of -55mV
What causes hyperpolarization?
the slow closing of the K+ channels.
How does the cell return to normal gradient after an action potential?
Na+/K+ pump returns cell to its normal gradient of K+ inside and Na+ outside
what is an example of a Voltage-gated Na Channel antagonists?
lidocaine
What speeds up the conduction of action potentials?
- larger axons
- schwann cells insulate
- knodes of ranvier
How do Knodes of Ranvier assist AP’s?
they are loaded with voltage gated channels to add extra support. AP’s jump from knode to knode causing saltatory conduction.
What neurotransmitter is released from the axon terminal in the motor end plate?
ACh - acetyl choline
Where is a somatic motor neuron cell body found in the spinal cord?
ventral horn
Which structural types of neurons may be sensory?
bipolar, unipolar
Which structural types of neurons may be motor?
multipolar
how are graded potential different from action potentials?
GRADED:
- decremental (get weaker over distance
- variable amplitudej (can be + or -)
- used for integration
- can happen in cell bodies or dendrites
- use ligand gated channels
- can sum
What ion has the greatest effect on the RMP? why?
K+ because it has more channels
What is the “blind spot”?
an area where a persons view is obstructed.
Where exactly is the blind spot?
entry of the optic nerve on the retina. (optic disc)
What is it about the anatomy of the eye that causes there to be a blind spot?
there are no photoreceptors in the optic disk.
Describe the pupillary eye reflex. Why is it considered consensual?
reflex that controls the diameter of the pupil in response to the intensity of light that falls on the retinal ganglion cells of the eye. it is considered consensual because what happens to one eye creates a response in both.
Loss of lens elasticity of the eye results in what? (usually occurs with age)
presbyopia
abnormal curvature of the cornea or lens results in what?
astigmatism
Which three cranial nerves are responsible for eyeball movement?
Oculomotor
Trochlear
Abducens
What is the fluid filling the anterior part of the eye? what is its function?
Aqueous humerous - nourishes the lens and cornea, maintains pressure
What is the function of the lens? how is it controlled?
the lens is what allows the eye to focus.
it is controlled by cilliary muscles that bend it.
what tool is used to look in the eye?
ophthalmoscope
What are the photoreceptors in the eye and their function?
- Rods - very sensitive; detect black/white vision
2. Cones - not very sensitive; detect color vision
What is the name of the common eye chart used?
Snellen eye chart
define fovea centralis.
a small depression in the retina of the eye where visual acuity is highest. The center of the field of vision is focused in this region, where retinal cones are particularly concentrated.
define accomodation.
eye focusing
What is the function of a motor neuron?
carries an AP to the effector (skeletal muscles)
What happens in the dorsal root ganglia?
The axon of sensory neurons run through it carrying sensory info to the CNS.
What is the function of the retina?
It is a thin layer of tissue that lines the back of the eye.
The function of retina is to capture light and convert it into electric signals that are translated into images by the brain.
What instrument is used to look in the ear?
Otoscope
What is the function of the eustachian tube?
equalize atmospheric pressure in the middle ear.
What is the eardrum called? function?
tympanic membrane - vibrates at the force of sound waves
name the organs within just the “vestibular apparatus” and provide functions.
- semicircular canals - each has an ampulla which houses a crista ampullaris - detect angular acceleration and deceleration
- vestibule which has the utricle and saccule - The sensory hair cells of the utricle and saccule provide information to the brain about head position when it is not moving. The utricle is sensitive to change in horizontal movement. The saccule is sensitive to the change in vertical acceleration (such as going up in an elevator).
which structures contribute to the middle ear? What are their functions?
- tympanic membrane - vibrates at the force of sound waves. passes waves through the
- tympanic cavity to the
- malleus, incus, stapes. The stapes presses against the
- oval window which transmits the sound waves to the cochlea
The membrane in the Orgtan of Corti that touches the tops of the “hairs” of the hair cells is the what?
tectorial membrane - gelatinous plate
Explain how the organ of Corti is able to detect different frequencies of sound.
through the variable stiffness of the basilar membrane
what is the function of the cochlea?
to transform the vibrations of the cochlear liquids and associated structures into a neural signal. (happens at organ of corti)
Define adrenergic receptor
Receptor that binds to epinephrine and norepinephrine
List each of the major endocrine glands and the hormones they secrete.
- Anterior pituitary gland - ACTH (adrenocorticotropic hormone), FSH, TSH, GH, LH, Prolactin
- Posterior pituitary gland - ADH, Oxytocin (milk letdown, uterine contractions)
- Thyroid gland - colloid produce T3 and T4 (thyroxine)
- Adrenal gland - Adrenal Medulla (middle) secretes epinephrine and norepinephrine, Adrenal Cortex (outer) secretes cortisol, aldosterone, and androgens
- Ovary - granulosa cells produce estrogen, corpus luteum produces estrogne and progesterone
- Testes - leydig cells produce testosterone
- Pancreas - Acinar cells secrete digestive enzymes, Islets of Langerhans secrete insulin from beta cells and glucagon from alpha cells
The mature stage of development of an ovarian follicle is called what? The cells of the follicle that produce steroids are called what?
Graafian follicle
Granulosa cells produce steroids
what is the normal range for blood glucose?
100mg/dL
What are the components of a knee jerk reflex arc.
- Stimulus - tendon stretches (tap to knee)
- Sensor - muscle spindle stretches and fires
- Sensory neuron - AP travels through sensory neuron (cell body outside of spinal cord - axon enters through the dorsal root ganglia
- Integrating Center - Sensory neuron synapses in the spinal cord
- Motor neuron - somatic motor neuron in ventral horn send out AP along their axon which travels to the..
- Target Effectors - 1. Quadricep muscle 2. Hamstring Muscle
- Response - 1. Quadricep contracts swinging lower leg forward, 2. hamstring stays relaxed allowing extension of leg
What are the components of a general muscle reflex arc?
- Stimulus - stretch
- Sensor - muscle spindles.
- Sensory neuron - carries sensory info to CNS
- Integrating center - processes info and determines course of action
- Motor Neuron - delivers action potential to effector
- Target Effector - carries out action
- Response
What is an EMG and what does it measure?
Electromyography
Measures electrical activity associated with depolarization and contraction of skeletal muscle motor units.
define Motor unit recruitment.
the changing/juggling of different motor units
Describe the function of the muscle spindle apparatus.
sends info about muscle stretch/length to the CNS and involved in reflexes.
Define fatigue as it applies to muscle physiology.
inability of a muscle to generate max force
Explain what an isometric contraction is.
contraction that generates force without changing the length of the muscle
Explain what an isotonic contraction is.
contraction that generates force by changing the length of the muscle.
Explain what concentric is.
causes muscles to shorten there by generating force
Explain what eccentric contraction is.
causes muscle to elongate in response to a greater opposing force.
define motor unit
a somatic motor neuron and all the skeletal muscle cells it innervates.
define summation
the second twitch will build off the first creating an increase in force generated.
define tetanus.
the state of constant contraction
define latent period.
the delay between the receipt of a stimulus by a sensory nerve and the response to it
