Exam 4 Study Guide

Function of a neuron (pg. 177)

The neuron enables the nervous system to act as a vast communication network. Neurons are responsible for the transmission of electrical signals.

Anatomy of a neuron (pg. 177)

Neurons have many shapes and sizes. Some are long, some are short, some are even 4 feet in length

T or F: Neurons are nonmitotic and therefore don't replicate or replace themselves when injured (pg. 177)

True

How do nerve impulses travel? (pg. 179)

The nerve impulse is an electrical signal that conveys information along the neuron. The nerve impulse is called the action potential

Precentral gyrus (pg. 188)

Located in the frontal lobe, directly in front of the central sulcus

Postcentral gyrus (pg. 188)

Located in the parietal lobe, directly behind the central sulcus

The cerebrum (pg. 186)

-Largest part of the brain.
-Divided into the right and left cerebral hemispheres
-The cerebral hemispheres are joined together by bands of white matter that form a large fiber tract called the corpus callosum

Each cerebral hemisphere has 4 major lobes: (pg. 186)

Frontal, parietal, temporal, occipital

Gyri is separated into grooves called ________?

Sulci (pg. 188)

A deep sulcus is called a ______?

Fissure (pg.188)

What do sulci and fissures do?

Separate the cerebrum into lobes (pg. 188)

Convolutions are also called what?

Gyrus (pg. 188)

What is the cerebral cortex?

"Thinking tissue" (pg. 188)

Gray matter

-Called the cerebral cortex.
-Forms the outer most portion of the cerebrum
-Composed primarily of cell bodies and interneurons and is therefore gray
-Allows us to perform higher mental tasks like learning, reasoning, language, and memory (pg. 186)

White matter

-Located directly below the cortex
-Composed primarily of myelinated axons that form connections between part of the brain and the spinal cord (pg. 186)

Phases of action potential

Resting, depolarization, repolarization

Resting membrane potential

Refers to the electrical charge difference across the membrane of the resting neuron. The resting cell is said to be polarized; no nerve impulse is being transmitted (pg. 179)

Depolarization

When the neuronal membrane is stimulated, a change occurs is the cell's electrical state. Changes the cell from negative to positive (pg. 179)

Repolarization

When the inside of the cell goes from positive to negative and returns to its resting state (pg. 179)

Functions of the CSF (cerebrospinal fluid) (pg. 195)

-Circulates within this space and forms a cushion around the brain and spinal cord
-Forms a third protective layer of the CNS
-Formed from the blood within the brain
-Composed of water, glucose, protein, and several ions

Function of myelin (pg. 179)

-Myelin protects and insulates the axon
-Nerve fibers covered by myelin are said to be myelinated
-Neurons that are not incased are called unmyelinated
-Myelination begins during the fourth month of fetal life and continues through teenage years

Function of the spinal cord (pg. 203)

The pathway for messages sent by the brain to the body and from the body to the brain

Spinal nerves

8 pairs of cervical nerves (Neck)
12 pairs of thoracic nerves (upper back)
5 pairs of lumbar nerves (lower back)
5 pairs of sacral nerves (what you sit on)
1 pair of coccygeal nerves (butt crack)

Sensory tract (pg. 204)

Carries information from the periphery, up the spinal cord, and toward the brain therefore called ascending tracts

Motor tracts (pg. 205)

Carry information from the brain, down the spinal cord, and towards the periphery therefore called descending tracts

Afferent nerves (pg. 218)

Brings sensory information from the different parts of the body, particularly the skin and muscles, to the CNS

Efferent nerves (pg. 218)

Brings motor information from the CNS to the skeletal muscles throughout the body

Ascending

Going up

Descending

Going down

Cranial nerves

Exit the brain and generally supply the head, neck, and shoulder areas

Cranial nerves perform four general functions that carry different types of information: (pg. 210)

-Sensory information for the special senses: smell, taste, vision, hearing, and balance
-Sensory information for the general senses: touch, pressure, pain, temperature, and proprioception
-Motor information that results in contraction of skeletal muscles
-Motor information that results in secretion of glands and the contraction of cardiac and smooth muscles

Nerve plexus (pg. 214)

Where nerve fibers come together again

The 3 major nerve plexuses are:

Cervical, brachial, lumbosacral (pg. 214)

Sympathetic nervous system (pg. 223)

-Fight or flight division
-Activated during periods of stress or danger
-Response is short-lived

Parasympathetic nervous system (pg. 223)

-Rest and digest or feed and breed
-Most active during quiet, non-stressful conditions
-Feelings of hopelessness

Thoracolumbar outflow (pg. 225)

The sympathetic nervous system

Craniosacral outflow (pg. 226)

The parasympathetic nervous system

Preganglionic fibers (pg. 225)

The axon of neuron 1, because it comes before [pre] the ganglion

Postganglionic fibers (pg. 225)

The axon of neuron 2, leaves the ganglion and extends to the effector or target organ

Effector organs of the autonomic nerves (pg. 222)

Glands, smooth muscles within organs, tubes and the heart

Cholinergic (pg. 226)

A fiber that secretes ACh (acetylcholine) as its neurotransmitter

Adrenergic (pg. 226)

A fiber that secretes NE (norepinephrine) as its neurotransmitter

The two major neurotransmitters: (pg. 226)

ACh (acetylcholine) and NE (norepinephrine)

ACh (acetylcholine) (pg. 226)

-ACh exerts its effect on its receptor,
-It is quickly degraded by AChE (an enzyme found in the synapse)
-Secreted by cholinergic fibers
-Diffuses to its receptor

NE (norepinephrine) (pg. 227)

-Secreted by adrenergic fibers
-Effects of NE are more prolonged because of termination manner
-Reabsorbed by the adrenergic nerve terminals
-The termination of NE is called reuptake

Muscarinic receptors (pg. 227)

Located on the effector or target organs (cardiac muscle, smooth muscle, and glands of the parasympathetic nerves)