The Nervous System - 7.6

What is the Nervous System?

a highly organized system that coordinates all the activities of the body

Neuron

nerve cell, basic structural unit of the nervous system

Cell body

contains nucleus

Dendrites

carry impulses toward the cell body

Axon

single nerve fiber that carries impulses away from the cell body

Myelin Sheath

fat covering which increases the rate of impulse transmission and insulates and maintains axon

Axon Terminals

known as synaptic boutons, at the end of axon branches, releases neurotransmitters to transmit signals

Neurotransmitter

located at the end of each axon, allows the nerve impulses to pass from one neuron to another

Nerves

a combination of many nerve fibers located outside the brain and spinal cord

Afferent/Sensory

all parts of the body to the brain or spinal cord

Efferent/Motor

from the brain and spinal cord to the muscles and glands

How many divisions are in the Nervous System?

2

Central nervous system (CNS)

consist of the brain and spinal cord

Peripheral nervous system (PNS)

consists of nerves

Theres how many pairs of cranial nerves?

12

Theres how many pairs of spinal nerves?

31

Somatic nervous system

controls skeletal system

Autonomic nervous system

controls involuntary body functions

Sympatheic

fast breathing and heart rate, slow digestive tract

Parasympathetic

slow breathing and heart rate, fast digestive tract

Brain

a mass of nerve tissue well protected by membrane and the cranium/skull

Cerebrum

largest and highest section of the brain controls voluntary movements like reasoning or memory

Cerebellum

section below the back of the cerebrum, responsible for muscle coordination, balance, posture, and muscle tone

Diencephalon

located between cerebrum and midbrain

Thalamus

acts as a relay center and directs sensory impulses to the cerebrum (regulates temp and recognizes pain)

Hypothalamus

regulates and controls appetite, water balance, sleep, and blood vessel constriction and dilation. Involves emotions

Midbrain

below cerebrum at top of the brainstem, conducts impulses for eyes and auditory reflexes

Pons

below midbrain in brainstem (chewing, tasting, salvia)

Medulla oblongata

lowest part of brainstem (regulates heartbeat, respiration, swallowing, coughing, and blood pressure)

Spinal cord

continues down from the medulla oblongata and ends at 1st/2nd lumbar vertebrae

Meninges

three membranes that cover and protect and brain and spinal cord

Dura mater

thick, tough, outer layer

Arachnoid membrane

delicate middle layer, weblike

Pia mater

innermost layer, closely attached to the brain and spinal cord

Ventricles

4, filled with cerebrospinal fluid

Cerebrospinal fluid

clear fluid, continually circulates between ventricles

Amyotrophic Lateral Sclerosis (ALS)

also known as Lou Gehrig’s disease, a chronic degenerative neuromuscular disease, cause is unknown

Carpal Tunnel

a painful hand/arm condition, swelling of the wrist, occurs when medial nerves/tendons pass through a canal/tunnel are pinched

Cerebral Palsy

non-progressive, non-contagious disturbance in voluntary muscle action that is caused by brain damage

Cerebrovascular Accident (CVA) or Stroke

occurs when the blood flow to the brain is impaired

TIA - Transient Ischemic Attack

ministroke (first 3 hours can help prevent brain damage)

Concussion

a traumatic brain injury that affects brain function caused by a blow to the head

Encephalitis

inflammation of the brain that is caused by a virus, bacteria, or chemical agent frequently contracted by a mosquito bite

Epilesy

known as seizure, abnormal surges in electrical impulses in the brain, petit mal is mild and grand mal is severe

Hydrocephalus

excessive accumulation of cerebrospinal fluid in the ventricles, called “waterhead”

Meningitis

inflammation of the meninges of the brain and/or spinal cord, caused by bacteria

Multiple sclerosis (MS)

chronic, disabling condition resulting from degeneration of myelin sheath

Neuralgia

nerve pain that can be so serve you cannot eat or sleep, use of medical marijuana helps

Paralysis

loss of voluntary muscle movement and coordination in some pairs

Parkinson’s disease

a chronic, progressive condition involving degeneration of brain cells, loss of grey matter in brain

Shingles

an acute inflammation of nerve cells caused by the herpes virus

The folds and ridges in the brain are called…

convolutions