Unit 4a Final Review Flashcards
Somatic nervous system
voluntary nerve control
autonomic nervous system
involuntary nerve control
grey matter
unmyelinated neuron
white matter
myelinated neuron
neurilemma
thin outer membrane on nerves in the PNS. promotes regeneration of damaged axons.
effector
responds to a signal (e.g. muscles)
affector
sends a signal out (converts stimulus into a nerve impulse)
reflex arc
involuntary unlearned response controlled by the spinal cord.
wave of depolarization
Many action potentials are generated along the cell membrane
what must happen in order for an action potential to occur?
the threshold level must be reached.
saltatory conduction
the way an electrical impulse skips from node to node down an axon (nodes of ranvier)
synapse
the small gap that separates neurons.
neuromuscular junction
the synapse when postsynaptic cell is a muscle cell.
neurotransmitters
released by the pre-synaptic neuron into the synapse.
excitatory neurotransmitters
triggers postsynaptic neuron to allow Na+ in. depolarization. promotes the generation of an action potential.
Inhibitory neurotransmittters.
causes K+ channels to open. Hyperpolarization. decreased likeliness of the generation of an action potential.
Greater # of synapses =
slower transmission speed.
Acetylcholine
acts as an excitatory neurotransmitter on many post-synaptic neurons.
cholinesterase
released to destroy acetylcholine.
Acetylcholine is the…
neurotransmitter of all neuromuscular junctions.
what causes the release of acetylcholine?
a build up of Ca2+ ions. It is also released by a vesicle via exocytosis.
summation
the additive effect of electrical impulses in multiple numbers coming on a neuromuscular junction. Individually these stimuli cannot generate a response, but together they can
Cerebrum
largest portion of the brain
cerbral cortex
outer layer of the cerebrum (grey matter)
left side of brain relates to…
language skills
right side of brain relates to…
problem solving, reasoning, spatial awareness.
Broca’s area
speaking
wernicke’s area
listening
Frontal lobe
voluntary muscles (walking, speech, personality, memory)
Temporal lobe
interpret’s sensory info (hearing, smell)
Parietal lobe
touch, pain, taste (temperature), sensations, emotions, interpreting speech
Occipital lobe
vision
Corpus callosum
communication between the two brain hemispheres.
Thalamus
interprets sensory information (relay station → sorts data from the spinal cord to appropriate parts of the brain)
Hypothalamus
maintains homeostasis (e.g. body temperature)
Limbic system
parts of brain associated with behavioural and emotional responses
olfactory bulbs
detect smell
midbrain
relay center for the eye and ear
hindbrain
balance, muscle control, & autonomic control.
Pons
relay station between the forebrain and hindbrain
medulla oblongata
acts as a connection between the PNS and CNS. Coordinating center for ANS regulating breathing, heart rate (autonomic functions)
cerebellum
balance, posture, and coordination
Brainstem =
Brainstem = midbrain + pons + medulla oblongata
Foramen magnum:
opening in the skull from which the spinal cord emerges from
Dorsal nerve tract
sensory info to the spinal cord
Ventral nerve tract
motor info from spinal cord to muscles/organs
sympathetic nervous system
fight or flight. increased heart rate / blood pressure. increased blood flow to skeletal muscles. digestion is inhibited.
parasympathetic nervous system
rest and digest. lowers breathing rate / heart beat. Vagus master off nerve.
Sensory receptors (role)
convert one energy form (information) about the external environment into electrochemical energy (nerve impulses), which are relayed to the CNS
sensory receptors are
the modified ends of sensory neurons that are activated by a specific stimulus
sensory adaptation
Constant exposure to a certain stimulus → insensitivity of the sensory receptor to that stimulus.
Neuron does not fire even though the stimulus is still present
perception is when..
the brain has interpreted the sensation
sensation is when…
the nerve impulse has reached the cerebrum
photoreceptors
eyes (rods/cones)
Chemoreceptors
tongue (taste buds), nose (olfactory cells, carotid arteries & brain (blood pH)
Mechanoreceptors:
ear (inner ear hair cells - balance & sound)
Thermoreceptors:
hot and cold (skin)
perception of taste is from
taste receptors and olfactory cells.
sclera
the white, fibrous, outermost layer of the eye
cornea
covers the front of the sclera; acts as the window (transparent); bends light towards the pupil
aqueous humor
a chamber of transparent fluid behind the cornea
choroid
the middle layer of the eye - contains blood vessels
iris
a thin circular muscle that controls the size of the pupil opening
lens
focuses image on the retina; found behind the iris
ciliary muscles
attached to ligaments that alter the shape of the lens
vitreous humour
Contains a cloudy, jelly-like material that maintains the shape of the eyeball. Permits light transmission to the retina
retina
innermost layer of eye
rods
extremely sensitive (stimulated by single photons of light). only black and white. most concentrated in edges of eye.
cones
colour-detecting sensors that require intense light
Cones are packed most density at the fovea centralis
fovea centralis
tiny depression in the back and center of the retina.
The most sensitive area of the eye; closely packed cones
blind spot
There are no rods and cones in the area in which the optic nerve comes in contact with the retina.
viewing close objects.
thicker lens, ciliary muscles contract, suspensory ligaments relax, pupil constricts (sharp focus),
viewing far objects
thinner lens, ciliary muscles relax, suspensory ligaments tighten pupil dilates (more light)
astigmatism
uneven curvature of the cornea
cataracts
lens becomes opaque
glaucoma
build-up of fluid in the anterior chamber to the lens
myopia (nearsighted)
elongated eyeball → focused image falls in front of retina
Hyperopia (farsighted):
short eyeball → image focuses behind the retina
Rhodopsin
light pigment found in the rods of the eye
Photopsin
light pigment found in cones; reacts only to certain light wavelengths
ear is involved with both
hearing and balance
Pinna
outer flap of the ear → acts as a sound funnel
auditory canal
carries sound waves to the eardrum.
Tympanic membrane (eardrum):
sound waves → mechanical vibrations
Ossicles:
three bones that amplify vibrations from the eardrum to the oval window (malleus/incus/stapes)
Oval window:
smaller than eardrum; amplifies sound
eustachian tube
air-filled tube that equalizes pressure between the internal and external ear. Also drains excess fluid to the nasal cavity
vestibule
Contains two small sacs, utricle and saccule, which determine the head position (static equilibrium)
semicircular canals
arranged at different angles. The movement of fluid within helps to identify body movement (dynamic equilibrium). (fluid moves hair/cilia).
cochlea
(snail) Contains two rows of hair cells that identify and respond to sound waves of different frequencies and intensities.
the saccule and utricle contains…
calcium stones called otoliths suspended in jelly. when this moves, hair receptors move.
when the oval window moves in…
the round window moves outward
organ of corti
long structure within the cochlea. Composed of 2 rows of hair cells, anchored to the basilar membrane.
basilar membrane
base layer of the organ of corti.
