Human Physiology Exam 2

UIOWA HHP:1300

Central nervous system

Brain + spinal cord

recieve and send information

Peripheral nervous system

cranial nerves and spinal nerves

communication

white matter

myelinated axons

gray matter

unmyelinated axons

afferent neurons

neurons that carry sensory information to the central nervous system

efferent neurons

neurons that transmit signals away from the central nervous system to muscles and glands.

schwann cells

neuroglial cells that myelinate peripheral neurons

oligodendrocytes

neuroglial cells that myelinate central nervous system neurons.

astrocytes

nurishment of neurons, form blood-brain barrier

microglia

cleaning debris / marcophage

ependymal cells

produce CSF

excitable tissues

undergo rapid changes in resting membrane potential and can change their resting potentials into electrical signals

Where is there more sodium

outside the cell than inside.

where is there more potassium

inside the cell than outside.

polarization

membrane potential other than 0mV

depolarization

the process of reducing the membrane potential, making it less negative than the resting potential.

repolarization

the process of restoring the membrane potential to its resting state after depolarization.

hyperpolarization

the process of increasing the membrane potential, making it more negative than the resting potential.

leaky channels

ions constantly slowly diffuse through

ligand-gated channels

channels that are opened chemically by neurotransmitters

voltage-gated channels

channels that open or close in response to changes in membrane potential.

mechanical-gated channels

channels that open in response to mechanical deformation of the cell membrane, sensor changes

what type of channels does K+ have

leaky and voltage gated

what channels does Na+ have

voltage-gated channels

what voltage do Na+ channels open

around -55 mV

graded potentials

magnitude varies with stimulus strength, gradua;;y decrease

action potential

breif, rapid change in membrane potential, all or none. begins at axon hillock

what is it when a graded potential reaches above threshold

action potential

sequence for action potentials

depolarization, peak, repolarization, hyper polarization, return to resting potential

saltatory conduction

action potential jump from one node to the next

excitatory postsynaptic potential (EPSP)

postsynaptic cell membrane depolarizes, less negative

Inhibitory postsynaptic potential (IPSP)

postsynaptic potential cell membrane hyperpolarizes, more negative

where is acetylcholinesterase (AChE) found

synaptic cleft

what is the function of acetylcholinesterase

breaks down ACh, which is taken back into presynaptic cell

divergence

one neuron to many neurons, motor

convergence

many neurons ot one neuron, sensory

conditions for postsynaptic neuron to fire

right number of active synapses, if synapses are excitatory or inhibitory

summation

more than one synapse needed to add input together to reach threshold

temporal summation

1 presynaptic neuron stimulating repeatedly, fast enough to reach threshold in postsynaptic neuron

Spatial summmation

multiple presynaptic neurons stimulate postsynaptic neurons to reach threshold

what is the largest part of the brain

cerebrum

frontal lobe

executive resaoning, control motor movement

parietal lobes

perception of senses

temporal lobe

auditory cortex

occipital lobe

visual cortex

insula

integration of sensory information with visceral responses

Positron emission tomography (PET)

injection of radionucleotide tracer, brain metabolism

magnetic resonance imaging (MRI)

uses magnet, protons charged and spin, looks at density

electroencephalogram (EEG)

tracks brain waves

what does the left hemisphere specialize in

usually dominant, language, analytical ability, talking and understanding

what does the right hemisphere specialize in

visuospatial, patterns

Broca’s area

understand language, but can not coordinate motor to speak

Wernicke’s area

responsible for ability to comprehend language and form words

where does parkinsons occur

basal nuclei

basal nuclei

suppress unwanted patterns of movement, releases dopamine

what makes up the limbic system

hippocampus, amygdala, hypothalamus, thalamus

function of limbic system

emotions, aggression, fear, “smell brain”, sex drive, reward and punishment behavior

short term memory

less than 30 seconds

long term memory

more than 30 seconds

non-declarative memory

simple skills, tying shoes - long term

declarative memory

facts and events

where does memory consolidation occur

temporal lobe, amygdala and hippocampud

if memory has an emotional component, what part of the brain is involved

amygdala

what makes up the diencephalon

thalamus and the hypothalamus

what does the brain stem do

regulate vegetative functions, HR and digestion

brain stem components

medulla, pons, midbrain

what is the midbrains main function

motor movement of eye, auditory processing

reticular activating system (RAS)

network of neurons projecting into cortex, activated by receiving sensory information, wakefulness

function/importance of sleep

concolidating memories, forming synapses

cerebellum

coordinates movement, maintains position of body, planning and initiating movement

what does damage to cerebellum lead to

ataxia, uncoordinated movement

how many pairs of spinal nerves leave spinal cord

31 pairs

ascending tract

carry sensory information up to brain

descending tract

carry motor information away from brain

spinal nerves

cluster of both afferent and efferent neurons

reflex

simple, response to a stimulus

reflex arc pathway

stimulus, receptor, sensory neuron/down afferent pathway, integrating center, motor neuron/efferent pathway, effector, response

somatic nervous system

voluntary, innervates skeletal muscle

autonomic nervous system

involuntary, innervates cardiac and smooth muscle, glands and fat