abeka biology 10 section 8.1

if u find something wrong or misspelt i am lit so sorry...im like barely alive rn

nervous system

one of the most amazing designs in God’s living creation

neurobiologist

a biologist who studies the nervous system

neurologist

a physician who specializes in disorders of the nervous system

central nervous system

includes the brain and the spinal cord

peripheral nervous system

consists of the nerves that branch from the brain and spinal cord

brain

the principal organ of the nervous system

cranium

what is the central nervous system protected by?

spinal cord

thick bundle of nerve fibers located within the spinal cavity

spinal nerves

transmit nerve signals to and from the rest of the body

cranial nerves

branch directly from the brain stem and transmit nerve signals to and from the eyes, ears, mouth, face, and scalp

meninges

composed of an outer layer called the dura mater, a middle layer called the arachnoid mater, and an inner layer called the pia mater

dura mater

one of the strongest tissues of the body; serves primarily as a flexible protective layer

arachnoid mater

composed of thin fibers, like the fibers of a spider’s web, that form an intricate three­-dimensional network around the brain

pia mater

forms a delicate covering that rests directly against the brain and spinal cord

cerebrospinal fluid

clear fluid that circulates through the fibers of the arachnoid mater, cushioning the brain when you bump your head

glial cells

support and insulate nerve tissue

neurons

the actual nerve cells

cell body

contains a nucleus (which controls its metabolic activities) and most of the nerve cell’s cytoplasm

dendrite

a short, branched extension of the cell that receives nerve impulses from other neurons and conducts them toward the cell body

axon

a long extension that relays nerve impulses from the cell body to other neurons

gray matter

found within the brain and spinal cord; consists largely of the cell bodies of neurons and is gray because the cell bodies lack the white, specialized covering known as myelin

myelin

white, specialized covering

white matter

composed of axons and glial cells that are white because of their myelin content

ganglia

masses of cell bodies

plexus

a network of interconnected nerve fibers going to or from a region

brachial plexus

located at the back of the neck and shoulder; branches to form the median nerve and other arm nerves

nerve center

group of cell bodies in the brain or spinal cord

medulla oblongata

peripheral nervous system

consists of nerves

nerves

bundles of nerve fibers (axons) branching from the brain and spinal cord and connecting the central nervous system to the extremities of the body

sciatic nerve

one of the longest nerves in the body; connects the leg extremities with the spinal cord in the lower back

• cranial

• spinal

two answer fill in the blank

there are twelve pairs of ________ nerves (branching directly from the brain) and thirty-­one pairs of _______ nerves (connected to the brain through the spinal cord)

mixed nerves

nerves contain both sensory and motor fibers

sensory nerve fibers

carry impulses from light, taste, sound, touch, and pain from other parts of the body to the spinal cord and brain for analysis

motor nerve fibers

carry impulses from the brain and spinal cord to produce action in muscles and organs

autonomic nervous system

the part of the peripheral nervous system that controls the heart and other internal organs

hypothalamus

controls the sympathetic and parasympathetic divisions of the autonomic nervous system

sympathetic division

generally responds to your body’s needs during increased activity and in emergency situations by causing heartbeat and breathing rates to increase, thus supplying more blood to your body so that you can respond quickly

parasympathetic division

acts as a balance to counteract the actions of the sympathetic division