Biol 2404 Lecture Exam II Review (Chapters 9 and 10)

Neurons

Individual cells in the nervous system that receive, integrate, and transmit information.

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

cell body of neuron

contains nucleus and organelles

Axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Central Nervous System (CNS)

consists of the brain and spinal cord

Peripheral Nervous System (PNS)

the sensory and motor neurons that connect the CNS to the rest of the body

sensory receptors

neurons that respond to stimuli and trigger electrical signals

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system

A subdivision of the peripheral nervous system. Controls involuntary activity of visceral muscles and internal organs and glands.

Myelin

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

Microglia

Act as phagocytes, eating damaged cells and bacteria, act as the brains immune system

Oligodendrocytes

Type of glial cell in the CNS that wrap axons in a myelin sheath.

Astrocytes

Provide structural and metabolic support for neurons.

ependymal cells

line cavities of the brain and spinal cord, circulate cerebrospinal fluid

Schwann cells

produce myelin in PNS

Nodes of Ranvier

a gap in the myelin sheath of a nerve, between adjacent Schwann cells.

multipolar neuron

a nerve cell that has many dendrites and a single axon

bipolar neurons

A neuron that has only two projections (one axon/one dendrite) from the cell body

unipolar neuron

a neuron with one process extending from its cell body

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

sensory neurons

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

motor neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

action potential

a neural impulse; a brief electrical charge that travels down an axon

resting potential of a neuron

its stable, negative charge when the cell is inactive

polarized membrane

An axon membrane at rest where the inside of the cell is negative compared with the outside of the cell

depolarized

when the membrane potential is less negative

Repolarization

Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing.

reflex arc

sensory receptor, sensory neuron, motor neuron, and effector that are involved in a quick response to a stimulus

patellar reflex

a reflex extension of the leg resulting from a sharp tap on the patellar tendon

Meninges

three protective membranes that surround the brain and spinal cord

dura mater

thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord

epidural space

space between the dura mater and the wall of the vertebral canal

arachnoid mater

middle layer of the meninges

pia mater

thin, delicate inner membrane of the meninges

cerebrospinal fluid (CSF)

circulates throughout the brain and spinal cord

spinal cord

Nerves that run up and down the length of the back and transmit most messages between the body and brain

spinal nerves

31 pairs of nerves arising from the spinal cord

Cerebrum

Area of the brain responsible for all voluntary activities of the body

cerebral hemispheres

The right and left halves of the cerebrum.

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

gyrus

A convoluted ridge between anatomical grooves.

Sulcus

shallow groove

fissure in brain

deeper grooves

Lobes of the cerebrum

frontal, parietal, temporal, occipital, insula

cerebral cortex

outer region of the cerebrum, containing sheets of nerve cells; gray matter of the brain

motor areas of cerebral cortex

control voluntary motor functions

motor speech area (Broca's area)

Location: frontal lobe - usually left side

Function: controls the activity of muscles of the vocal cords to facilitate speech

choroid plexus

A highly vascular portion of the lining of the ventricles that secretes cerebrospinal fluid.

Diencephalon

thalamus, hypothalamus, epithalamus

functions of hypothalamus

Master control of the autonomic nervous system

Master control of the endocrine system

Regulation of body temperature

Control of emotional behavior

Control of food intake

Control of water intake

Regulation of sleep-wake (circadian) rhythms

limbic system

neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

Brainstem consists of

midbrain, pons, medulla oblongata

Midbrain

A small part of the brain above the pons that integrates sensory information and relays it upward.

medulla oblongata function

regulating vital function (breathing, digestion, heart rate)

Cerebellum

A large structure of the hindbrain that controls fine motor skills.

cranial nerves

12 pairs of nerves that carry messages to and from the brain

CN I

Olfactory Nerve;

Sensory

Smell

CN II

Optic - vision

CN III

Oculomotor (motor)

CN IV

Trochlear (motor)

CN V

Trigeminal (sensory and motor to face)

CN VII

-facial

-assess mouth for taste

-assess the face for symmetrical movement

CN VI

Abducens (motor)

CN VIII

Vestibulocochlear (sensory to middle ear)

CN IX

-glossopharyngeal

-assess mouth for taste

-assess mouth for movement of soft palate and the gag reflex

-assess swallowing and speech

CN X

vagus nerve (somatic and sensory)

CN XI

accessory nerve (motor to neck)

CN XII

Hypoglossal (tongue movement)

dorsal root

contains axons of sensory neurons

ventral root of spinal nerve

This structure contains the cell bodies of the somatic motor neurons that innervate the skeletal muscles.

plexus

large, interlacing network of nerves

parasympathetic nervous system

a set of nerves that helps the body return to a normal resting state

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

preganglionic neuron

in the autonomic nervous system of the PNS, a neuron that has its cell body located in the CNS and whose axon extends into the PNS to synapse with a second neuron at an autonomic ganglion (the second neuron's axon synapses with the target organ)

postganglionic neuron

in the autonomic division of the PNS, a neuron that has its cell body located in an autonomic ganglion (where a pre-ganglionic neuron synapses with it) and whose axon synapses with the target organ

ganglion

collection of nerve cell bodies in the peripheral nervous system

Norepinephrine (NE)

the neurotransmitter used by the sympathetic division of the autonomic nervous system at the post-ganglionic organ-level (synapse)

Acetylcholine (ACh)

neurotransmitter used by the sympathetic and parasympathetic divisions by the preganglionic fibers

Chemoreceptors

chemical sensors in the brain and blood vessels that identify changing levels of oxygen and carbon dioxide

pain receptors

respond to tissue damage

Thermoreceptors

respond to changes in temperature

Mechanoreceptors

respond to touch, pressure, vibration, stretch, and itch

Photoreceptors

respond to light

Sensation

stimulation of sense organs

olfactory receptors

nerve endings that act as the receptors for the sense of smell

taste cells

receptor cells that are sensitive to taste

taste senstations

sweet, sour, salty, bitter and umami

eardrum

a thin membrane that marks the beginning of the middle ear; sound waves cause it to vibrate

auditory ossicles

malleus, incus, stapes

labrinyth of ear

communicating chambers and tubes, including semicircular canals and a cochlea

semicircular canals

passages in the inner ear associated with maintaining equilibrium

cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

vestibule of ear

The portion of the inner ear that senses the position of the head. Its sensory epithelium is contained in two saclike spaces: the utricle and the saccule.

lacrimal gland

produces tears

extrinsic muscles

Six muscles attach to the outer surface of the eye;Produce eye movements

Cornea

The clear tissue that covers the front of the eye

Sclera

white of the eye