5-CH21-Pehrson_Hailey

aderal glands

glands that are located just above the kidneys and contain two parts, the adrenal cortex and the adrenal medulla

afferent

term that describes sensory transmitters that send impulses from receptors in the skin, muscles, and joints to the central nervous system

aqueous humor

a clear fl uid in the front of the eye that maintains pressure and nourishes the cornea and lens

axon

a long, tail-like projection on a neuron, which takes information from the cell body out to the muscles

brainstem

area of the brain that controls the smooth muscles of the heart and lungs; also known as the vital functions cente

cell body

part of a neuron that contains the nucleus

central nervous system

the brain and spinal cord

cerebellum

the second-largest area of the brain, which coordinates incoming and outgoing messages to produce smooth skeletal movements

cerebral cortex

the outer surface of the cerebrum, which has many bumps and grooves

cerebrum

the largest part of the brain, which is formed by the four lobes of the cerebral cortex

choriod

a membrane that supplies blood to the eye and controls the light refl ected to the retina

cochlea

a fl uid-fi lled chamber of the inner ear that is used for hearing

cornea

a transparent tissue through which light enters the eye

cranial nerves

12 pairs of nerves that provide connections from the brain to the head and neck

dendrites

branches of a neuron that collect stimuli and transport them to the cell body

efferent

term that describes motor transmitters that carry impulses from the central nervous system out to the muscles and glands

forebrain

the largest part of the brain, which includes the cerebrum, basal ganglia, and limbic system

frontal lobes

lobes of the brain that are located at the forehead and are responsible for voluntary muscle control, thinking, memory, language, judgment, creativity, and personality

ganglion

a swelling located between two neurons

hindbrain

the part of the brain that includes the cerebellum and brainstem

homeostasis

a state of balance between interdependent elements

hormone

a chemical used to send messages from an endocrine gland to a target organ

hypothalamus

the brain’s center for emotions and instincts, which controls pleasure, pain, sleep, hunger, and thirst

innervate

to provide an area with a nerve connection to the brain

islets of langerhans

clusters of cells located on the pancreas that make the hormones insulin and glucagon

lens

a transparent, fl exible structure that focuses light at the back of the eye

meninges

three tough layers of tissue covering the brain and spinal cord, including the dura mater, arachnoid mater, and pia mater

mental health

a component of wellness that combines emotional, psychological, and social well- being

midbrain

the section of the brain that includes the thalamus, hypothalamus, pituitary gland, and pineal gland

myellin

a fatty layer that protects the axons of some nerves

negative feedback system

mechanism that reduces a body function in response to a stimulus, such as a hormone

neuron

a nerve cell

neurotransmiter

a chemical used to carry a signal from an axon to a receptor cell to pass along a message

occipital lobes

the smallest of the brain’s lobes, which are located in the back of the skull and control sight, visual-spatial processes, memory, and storage

olfactory bulb

the thickened end of the olfactory nerve that sends sensory impulses to the olfactory region of the brain

ossicles

bones that transfer vibrations from the middle ear to the inner ear, including the malleus, incus, and stapes

papillae

tiny bumps on the tongue that house taste buds

paralysis

a condition that limits the ability to move certain parts of the body

parathyroid glands

four tiny glands that are located on the back of the thyroid and which secrete a hormone that triggers the release of calcium from bones

parental lobes

lobes of the brain that are located behind the frontal lobes and integrate sensory information from the skin, internal organs, muscles, and joints

peripheral nervous system

term for the sensory and motor nerves that go out to the body’s extremities

pituitary gland

gland that releases hormones that affect the operation of many other glands in the body; also called the master gland

plexus

an interwoven combination of spinal nerve roots through which messages pass

primary motor cortex

an area of the frontal lobe that directs muscle movement through efferent neurons to muscles in the body

primary sensory cortex

an area of the parietal lobe dedicated to gathering and interpreting information regarding the fi ve senses of the body from afferent neurons

pupil

the opening through which light rays enter the eye

receptor

a nerve cell that receives stimuli

reflex

an involuntary response of the nervous system

sclera

the tough, fi brous outer layer of the eye; also known as the white of the eye

spinal nerves

31 pairs of nerves that connect the spinal cord to the rest of the body

synapse

a tiny gap between an axon and a receptor cell

taste bud

a sensory cell that converts fl avors into electrical signals

temporal lobes

lobes of the brain that lie near the ears and control hearing, balance, emotions, speech planning, and memory associations

terminal branches

branches located at the end of an axon, which connect to other cells

thalamus

area of the brain that acts as a relay station for sorting, interpreting, and directing sensory signals to the appropriate area of the cerebral cortex

thyroid gland

the largest endocrine gland in the body, which controls energy, metabolism, and calcium levels in the blood

tympanic membrane

thin membrane that divides the outer and middle ear and changes sound waves into vibrations; also known as the eardrum

vestiblular canals

chambers in the ears that sense movement of fluid

vitreous humor

a clear fl uid that maintains the eye’s shape