Download Nervous System Notes File

The Nervous System
I.
Function and Structure of the Nervous system
Coordinates all the activities in your body; the brain, spinal cord and nerves work
together
II.
a. Central Nervous System
i. Brain and Spinal Cord
ii. Receives messages from the nerves in the peripheral nervous
system, interprets them, and sends out a response
iii. Impulses can move at speeds up to 280 miles per hour
b. Peripheral Nervous System
i. Nerves that extend from the brain, spinal cord and sensory
receptors
ii. Sensory receptors are found in places like the skin that sense
pressure, temperature or pain
The Central Nervous System
a. Brain – integrates and controls the activities of the nervous system
i. Helps you receive and process messages, think, remember,
reason, and coordinate muscle movements
ii. Adult brains weigh up to three pounds
iii. Uses 20% of oxygen we inhale
iv. The brain is protected by the skull, cranial meninges and
cerebrospinal fluid
1. Cranial Meninges – made up of three layers of tissue
v. Divided into three main divisions: the cerebrum, the
cerebellum and the brain stem
b. The Cerebrum – largest and most complex part of the brain
i. Covered with gray matter
ii. Center for conscious thought, learning, and memory
iii. Divided into two hemispheres – the right hemisphere controls
the left side of the body and the left hemisphere controls the
right side of the body
iv. Left Hemisphere: language, reasoning and the ability to
analyze and think critically about math and science
v. Right Hemisphere: process music, art and spatial relationships
vi. Both Hemispheres have 4 Lobes or sections
1. The Frontal Lobe – Controls Voluntary movements; has a
role in the use of language, involved in intellect and
personality
2. The Parietal Lobe – sensory information such as heat,
cold, pain, touch and body position and space
3. The Occipital Lobe - vision
4. The Temporal Lobe – hearing and smell; memory,
thought and judgment
c. The Cerebellum- second largest part of the brain
i. Movement of skeletal muscles
ii. Helps with body’s posture and balance
d. The Brain Stem – a three-inch stalk of nerve cells and fibers that
connects the spinal cord to the rest of the brain
i. Medulla Oblongata
1. Regulates heartbeat and breathing
2. Reflexes such as coughing, sneezing and vomiting
3. Hearing and tongue movement to control speech and
swallowing
ii. Pons
1. Pathway for nerve impulses
2. Helps regulate breathing
3. Controls muscles of the eyes and face
iii. Midbrain
1. Controls eyeball movement and pupil size
2. Reflex response of turning your head when you hear
something
iv. Thalamus
1. Receives sensory information from the eyes, ears and
skin
III.
IV.
2. Has a role in feeling pain
v. Hypothalamus
1. Controls regulation of body temperature, appetite and
sleep
2. Pituitary gland – controls metabolism, sexual
development and emotional responses
The Peripheral Nervous System – carries messages between the CNS and
the rest of the body
a. The Autonomic Nervous System – controls involuntary functions
i. The Sympathetic Nervous System – controls what happens
when you are startled
1. Fight or flight response
2. Heart rate increases, breathing rate increases, blood
flow increases
3. Reflex – a spontaneous response of the body to a
stimulus
ii. The Parasympathetic Nervous System – does the opposite of
the sympathetic nervous system
1. Slows down heart rate and breathing rate
b. Somatic Nervous System –
i. relays messages from receptors in the eyes, ears, nose, tongue
and skin to the CNS
ii. relays messages from the CNS to skeletal muscles
Problems of the Nervous System
a. Can result from damage to nerve cells or injury to the brain or spinal
cord
i. Falls, sports, car accidents, etc.
ii. Drugs and alcohol destroy brain cells
b. Head injuries
i. Concussion
1. Could cause temporary loss of consciousness
2. Caused by a bump, jolt or blow to the head that causes
the brain to not function normally
V.
ii. Contusion
1. Also caused by a blow to the head
2. Bruising of the brain tissue that could cause swelling
3. Can cause bleeding in the brain which will form a clot
iii. Major Trauma
1. Could cause a person to go into a coma
c. Spinal Injuries
i. Any swelling around the spinal cord could cause a temporary
loss of function
ii. If the spinal cord is severed or damages beyond repair
paralysis usually results
iii. Quadriplegia
1. Caused by injury to the upper part of the spinal cord
2. Causes paralysis of both upper and lower limbs
iv. Paraplegia
1. Caused by injury that occurs at the lower part of the
spinal cord
2. Causes paralysis of both lower limbs
Degenerative Diseases – diseases that cause cells and tissues to deteriorate
over time
a. Parkinson’s Disease
i. Caused by the destruction of nerve cells in the area of the
brain that coordinates movement
ii. More and more nerve cells are destroyed over time
iii. Uncontrolled tremors, increased muscle rigidity
iv. No known cause or cure
b. Multiple Sclerosis
i. The immune system attacks the myelin sheath around the
axons of the neurons
ii. Voluntary muscle movement is affected (example: eventually
can’t walk)
iii. No cure
c. Alzheimer’s Disease
VI.
VII.
i. Neurons in the brain are destroyed
ii. Can’t transmit nerve impulses
iii. Loss of memory, confusion and mental deterioration
iv. Cause unknown, no cure
Other Disorders and Problems
a. Epilepsy – disorder of the nervous system that is characterized by
recurrent seizures
i. Seizures – sudden episodes of uncontrolled electrical activity in
the brain
ii. Medications can help
b. Cerebral Palsy – a group of nonprogressive neurological disorders
that are the result of damage to the brain before, during or just after
birth or in early childhood
i. Caused by infections, head injury or exposure to radiation
ii. Physical therapy and braces help patients walk and be
independent
Tests for the Brain
a. CT or CAT scan – x-rays
b. PET scan – Uses radiation to produce 3D, colored images
i. Dye is injected
ii. Tests brain function
c. MRI
i. Uses radio waves and magnetic fields to produce brain images