Human phys final

Pacinian corpuscles

respond to deep pressure and vibration

The amplitude of a graded potential decreases as the distance from the graded potential's point of origin _______

increases

Summation is

the process by which graded potentials add together.

What does the white matter in the spinal cord consist of

primarily of bundles of myelinated axons of neurons.

transduction pathway for olfaction

the olfactory pathway conveys olfactory information from olfactory receptors in the nose to processing centers in the cerebral cortex and limbic system

What is a feedback

is a cycle of events in which a controlled variable is monitored, evaluated, changed, remonitored, reevaluated, and so on.

Homeostasis

is the maintenance of relatively stable conditions in the body's internal environment. -a dynamic steady state. -Steady state is not the same as equilibrium.

pothotransduction

is the process by which light energy is converted into a receptor potential

What is an after-hyperpolarizing phase?

the membrane potential temporarily becomes more negative than the resting level

The resting membrane potential is determined by three factors which are___

(1) unequal distribution of ions in the ECF and cytosol, (2) differences in membrane permeability to various ions, and (3) action of the Na+/K+ ATPases.

Componets of Feedback Systems

basic components: a receptor, control center, and effector.

Example of positive feedback system?

birth of a baby

example of feedforward control

cephalic phase of digestion

the white matter of the spinal cord function

tracts in the spinal cord serve as the highways for action potentials propagation. sensory input travels along these tracts toward the brain and motor output travels along these tracts toward skeletal muscles and other effector tissues.

transduction pathway for pacinian corpuscle

transaction in a pacinian corpuscle involves the opening of cation channels in response to a mechanical stimulus (vibration)

sympathetic nervous system function

- contraction of radial smooth muscle in iris of eye to cause pupillary dilation -increased contraction of cardiac muscle of heart to cause an increase in heart rate and an increase in force of contraction -increased breathing and relaxation of smooth muscle in bronchial tubes of lungs, resulting in bronchodilation -relaxation of smooth muscle in walls of blood vessels (vasodilation) that supply essential organs such as the brain, heart, liver, adipose tissue, and skeletal muscles -contraction of smooth muscle in walls of blood vessels (vasoconstriction) that supply nonessential organs such as digestive organs and glands, kidneys, and urinary bladder -breakdown of nutrient reserves to provide energy for the stressful situation

electrical excitability

The ability to produce action potentials in response to stimuli

When the response makes the membrane more polarized (inside more negative), it is termed a

hyperpolarizing graded potential

What regulates Homeostasis?

feedback systems.

parasympathetic nervous system function

-contraction of circular smooth muscle in iris of eye to cause pupillary constriction -decreased contraction of cardiac muscle of heart to cause a decrease in heart rate -reduced breathing and increased contraction of smooth muscle in bronchial tubes of lungs, resulting in bronchoconstriction -increased activity of the digestive system due to increased secretion of digestive glands and increased contraction of GI smooth muscle -contraction of smooth muscle in urinary bladder, resulting in urination

What is positive feedback system?

A system strengthens or reinforces a change in a controlled variable.

what happens on the on pathway in vision

in the on pathway glutamate is an inhibitory neurotransmitter at the synapse between a bipolar cell and ganglion cell

What is an example of negative feedback system?

Example: body temperature - blood pressure

the equilibrium pathway

From hair cells of the semicircular ducts, utricle, and saccule, vestibular information is conveyed along the vestibular branch of the vestibulocochlear (VIII) nerve and then to the brain stem, cerebellum, thalamus, and cerebral cortex.

transduction pathway for vision

Visual phototransduction is the process by which photon absorption by visual pigment molecules in photoreceptor cells is converted to an electrical cellular response.

the visual pathway

at the optic chasm half of the axons from each eye cross over to opposite sides of the brain

phases of action potential

a depolarizing phase and a repolarizing phase

An action potential that occurs in a muscle fiber is called

a muscle action potential or muscle impulse.

A ligand-gated channel opens or closes in response to a______

a specific ligand (chemical) stimulus. Example: acetylcholine -participate in the generation of graded potentials.

What are action potentials?

allow communication over long distances in the body. -a sequence of rapidly occurring events that decrease and reverse the membrane potential and then eventually restore it to the resting state.

What are graded potentials?

are used for short-distance communication only -a small deviation from the membrane potential that makes the membrane either less polarized (inside less negative) or more polarized (inside more negative).

what does the gray matter in the spinal cord consist of

dendrites and cell bodies of neurons, unmylinated axons and neuroglia

hen the response makes the membrane less polarized (inside less negative), it is termed a

depolarizing graded potential

Which channels are open during the depolarizing phase? During the repolarizing phase?

depolarizing phase: the voltage-gated open depolarizing phase: voltage gated Na channel close ( Innactivated ) voltage gated K channels open

What is feedfoward control?

events occur in anticipation of a change in a controlled variable.

sympathetic nervous system function

fight or flight

transduction pathway for olfactory

from hair cells of the cochlea auditory information is conveyed along the cochlear branch of the vestibulocochlear nerve and then to the brain stem, thalamus and cerebral cortex

what happens in the off pathway of vision

glutamate is an expiatory neurotransmitter at other synapses

A mechanically-gated channel opens or closes in response to________

mechanical stimulation in the form of touch, pressure, tissue stretching, or vibration -mechanically-gated channels are involved in the formation of graded potentials.

The voltage that exists across the plasma membrane of a cell is called

membrane potential

A voltage-gated channel opens in response to a change in

membrane potential (voltage). -example: voltage-gated Na+ channels, and voltage-gated Ca2+ channels. -oltage-gated channels are responsible for the generation and conduction of action potentials.

What is an action potential that occurs in a neuron?

nerve action potential or nerve impulse.

How do leak channels open and close

randomly alternate between open and closed positions. -Leak channels are important for establishing the resting membrane potential.

the gray matter of the spinal cord function

receives and integrates incoming and outgoing information

Operation of the Neuromuscular Junction

refers to the synapse between a somatic motor neuron and a skeletal muscle fiber

parasympathetic nervous system function

rest and digest

What is negative feedback?

reverses a change in a controlled variable. -Most controlled variables in the body are regulated by negative feedback systems.

transduction pathway for gustation

the gustatory pathway conveys taste information from gustatory cells in taste buds to processing centers in the cerebral cortex, limbic system, and hypothalamus.

What happens to the membrane potential during depolarizing graded potential?

the membrane potential is inside less negative than the resting level;

What happens to the membrane potential during hyperpolarizing graded potential,?

the membrane potential is inside more negative than the resting level.

What happens during the repolarizing phase, or rising phase?

the membrane potential is restored to the resting state of −70 mV.

What happens during the depolarizing phase, or rising phase,

the negative membrane potential becomes less negative, reaches zero, and then becomes positive.