Bio 30 Unit A test review

Neurons

the functional units of the nervous system that respond to physical and chemical stimuli

glial cells

the cells that support and nourish the neurons (also known as schwaan cells)

Sensory neurons

relay information about the environment to the CNS (five senses)

Interneurons

link sensory neurons and motor neurons in the body

Motor neurons

carry nerve impulses from CNS to the effectors (muscles and glands)(movement)

cell body

contains the nucleus and where all the metabolic reactions occur within the cell

Dendrites

branching terminals that carry information to the cell body (both sensory and motor)

Axon

extension of the cytoplasm that carries nerve impulses from the dendrites to the effectors

Myelin sheath

A layer of fatty tissue that covers the axon and protects it from losing charged ions formed by schwonn cells

Nodes of Ranvier

the gaps in between the myelin sheath

true or false: unmyelinated nerve fibres transmit nerve fibres faster because of salitory conduction

false

white matter

myelinated neurons

grey matter

unmyelinated neuron cell bodies and short, unmyelinated axons

How is a electrochemical signal formed?

unequal concentration of positive ions across a membrane

electrical current

a faster current that diminishes near the end and uses external source to generate energy

Nerve impulse

a slower process that remains strong at the end and uses cellular energy(ATP) to move ions across a cell membrane

membrane potential

when one is more positive than the other

resting membrane potential

-70mV

Polarization

The process where the inside of the membrane is negative and the outside is positive. Occurring due to a sodium potassium pump that moves potassium to the inside and the sodium to the outside

Action potential

the all or non electrical signal that has a domino effect across the membrane in the axon

threshold potential

-55mV

Depolarization

the process where the sodium channels open up and the sodium ions flood into the inside of the membrane turning the inside of the membrane positive and the outside negative

repolarization

the process where the potassium channels open up again and the potassium ions move from high to low and go to the outside of the axon

hyperpolarization

where the potential dips too low and both the sodium and potassium channels are opened and the process of polarization occurs again

refractory period

the recovery time before a neuron can produce another action potential

synapse

the connection between two neurons (also synaptic cleft)

Neuromuscular junction

synapse between a motor neuron and muscle cell(not in direct contact)

Synaptic terminal

where one impulse will travel from one end to the opposite end

synaptic cleft

the space between synaptic terminals

neurotransmitters

chemicals that move from one neuron to the next that carry signals

acetylcholine

most common neurotransmitter that causes depolarization

presynaptic neuron

the neuron that releases the neurotransmitters

postsynaptic neuron

the neuron that accepts the neurotransmitters

Excitatory effect

a process that lowers the threshold and causes depolarization in the postsynaptic neuron

Inhibitory effect

increases the threshold and prevents the postsynaptic neuron from depolarizing using potassium ions

cholinesterase

the enzyme that hunts down and breaks down acetylcholine and stops the depolarization

Norepinephrine

helps control alertness and arousal

dopamine

controls body movements and linked to sensations of pleasure

serotonin

regulates temperature and sensory perception(involved in mood control)

endorphins

Acts as a natural pain killer in the brain ( also affects emotional areas of the brain)

GABA

an inhibitory neurotransmitter in the brain

Summation

when one postsynaptic neuron is excited/inhibited by more than one presynaptic neuron. Thus several neurons converge and release their neurotransmitters towards one neuron

spinal cord

a primary part of the CNS that branches out from the centre of your body through nerves

Brain

a primary part of the CNS that is the main centre for homeostasis, intelligence, consciousness and emotion

hindbrain

composed of the cerebrum, medulla oblongata, and pons

cerebellum

a walnut-shaped part of our brain that controls balance, fine voluntary motor skills, and unconscious coordination of posture

medulla oblongata

responsible for the continuous rate control within our body like heart and blood rate (automatic)

Pons

infront and above the medulla oblongata and is considered the relay centre in the brain for neurons

Midbrain

a part of the brain that above the pons and controls the relay of visual and auditory information between the hindbrain and the forebrain

Forebrain

composed of the cerebrum, thalamus, and hypothalamus

Thalamus

the base of the forebrain that consist neurons that provide connections mainly in the forebrain and hindbrain

Hypothalamus

below the thalamus and regulates the body's internal environment, emotions, hormones and coordination of the pituitary gland

cerebrum

largest part of the brain which controls intellect, memory conciousness and language

cerebral cortex

the covering of grey matter on the outside of each half of the cerebrum that controls language, memory personality, vision and conscious thought

left brain

the intellectual and logical side

right brain

the more creative and imaginative side

occipital lobe

receives and analyzes visual information

temporal lobe

responsible for auditory learning (wernickes)

pareital lobe

responsible for sensory information (pain,pressure,position,touch temperature)

frontal lobe

integrate info from other parts of the brain and control reasoning, critical thinking, memory and personality.

somatic system

voluntary control in the PNS

autonomic system

involuntary control

sympathetic nervous system

your fight or flight reaction that releases norepinephrine when the body is put in a stressful situation

parasympathetic nervous system

your rest or digest reaction that activates when the body is resting

impulse-transmission pathway

sensory input->integration-> motor output

reflex arc

the involuntary reaction that our body has to protect us from potential danger (sensory receptor->sensory input->integration->brain+SC->motor output->effector

Sclera

external white layer of the eye

cornea

the transparent part of the eye that bends light rays into the eye

choroid

the intermediate layer of the eye that absorbs stray light not detected by the photoreceptors

iris

regulates the amount of light entering the eye by expanding or constricting the eye

pupil

the opening of the eye( black circle)

Ciliary muscles

changes the shape of the lens in order to focus

retina

internal layer made up of rods,cones and the fovea centralis

rods

photoreceptors that are sensitive to dim light and movement

cones

photoreceptors that and different to different wavelengths of light or colour

fovea centralis

contains a high density of cones and rods and provides acute vision

ganglion cell

the projection neurons of the retina

bipolar cell

a cell that has two extensions that act as pathways

amacrine cell

interneurons in the retina that are responsible for 70% of input to ganglion cells

lens

focuses light rays onto the fovea centralis

vitreous humor

helps maintain the shape of eyeball and supports the surrounding cells

aqueous humour

maintains the shape of the cornea and providing oxygen and nutrients

optic nerve

sends auditory info to the brain for it to process it and to interpret it

blindspot

where the ganglion cells merge to the optic nerve where there are no photoreceptors

acutity

sharpness of vision(like our resolution)

Accomodation

charges optical power to maintain a clear image or focus on an object (the changing of our lens shape)

adaptation

ciliary muscles that will flatten or thicken the lens the focus the image on the retina(what causes accommodation)

binocular vision

using two lenses to view one image

peripheral vision

seeing an image that is in our periphery(3D image)

image focussing

how our eye flips an image within our brain

myopia

nearsightedness where the eyeball is elongated and you need and concave lens to correct

hyperopia

farsightedness where the eyeball is shortened and you need a convex lens to correct

astigmatism

uneven curvature of the cornea

outer ear

an air filled part of the ear that consists of the pinna and the auditory canal

pinna

the outer flap of the ear that enhances sound vibrations and sends them to the auditory canal

auditory canal

the canal that leads to the tympanum and amplifies sound waves also where ear wax and hairs are found to block foreign things from entering

middle ear

an air filled part of the ear that contains the tympanum, ossicles and eustachian tube

tympanum

a round elastic structure that vibrates in response to sound waves that are later passed onto the ossicles(eardrum)

ossicles

three tiny interconnected that pass from one to another the names for these names are the hammer/malleus, anvil/incus, stapes/stirrups

Eustachian tube

where the middle ear connects to the throat and when there is a pressure change in our surroundings then the pressure changes in our middle ear (popping of our ears)