1. Central Nervous System Communication and coordination
system of the body
Seat of intellect and reasoning
Consists of the brain, spinal cord,
and nerves

2. Neuron Dendrites Nerve cell
Transmits a message from one cell to the next
Has a nucleus, cytoplasm, and cell membrane
Dendrites
Nerve cell processes that carry impulse to cell body
May be one or many

3. Neurilemma (Myelin Sheath)
Axon
Carries impulse away from cell body
Only one per neuron
Neurilemma (Myelin Sheath)
Covering that speeds up the nerve impulse along the axon
Myelin is a fatty substance that protects the axon

4. Sensory Neurons (Afferent)- emerge from the skin or sense organs, carry impulses to spinal cord and brain
Motor Neurons (Efferent)- carry messages from brain and spinal cord to muscles and glands
Associative Neurons (Interneurons)- carry impulses from sensory neurons to motor neurons

5. Synapse- space between neurons, messages go from one cell to the next
Nerve impulse- a stimulus creates an impulse. The impulse travels into the neuron on the dendrite(s) and out on the axon. At the end of the axon, a neurotransmitter is released that carries the impulse across the synapse, to the next dendrite.

6. Divisions of the Nervous System
Central nervous system- brain and spinal cord
Peripheral nervous system- cranial nerves and spinal nerves

7. Divisions of the Nervous System
3. Autonomic nervous system- includes peripheral nerves and ganglia (mass of nerve cell bodies outside the CNS) , supplies heart muscle, smooth muscle and secretory glands, involuntary action
4. Somatic System – voluntary control

8. The Brain 3 lb mass of soft nervous tissue 100 billion neurons
Protected by skull, three membranes called meninges, and cerebrospinal fluid
Adequate blood supply is needed, brain tissue will die in 4-8 minutes without O2
Divided into 4 major parts: cerebrum, diencephalon, cerebellum, brain stem

9. Coverings of the Brain (Meninges)
Dura mater- outer brain covering, lines the inside of the skull, tough dense fibrous connective tissue. Subdural space- between dura and arachnoid (sub- below/dura) Arachnoid- middle layer, resembles fine cobweb

10. Pia mater- covers the brain’s surface, comprised of blood vessels held together by connective tissue
Subarachnoid space- between arachnoid and pia mater, filled with cerebrospinal fluid (CSF)- acts as a liquid shock absorber and source of nutrients for the brain

12. Ventricles of the Brain
Brain contains four cavities filled with cerebrospinal fluid called cerebral ventricles.
Right and left lateral ventricles
Third ventricle- behind and below the lateral ventricles
Fourth ventricle is below the 3rd, in front of the cerebellum and behind the brain stem
Choroid plexus- network of blood vessels lining the ventricles which helps in the formation of cerebrospinal fluid

13. Cerebrospinal Fluid (CSF)
Forms inside ventricles of the brain
Serves as a liquid shock absorber protecting the brain and spinal cord
Blood-brain barrier- choroid plexus capillaries prevent substances (like drugs) from penetrating brain tissue- this makes infections, like meningitis, difficult to cure
Lumbar puncture- removal of CSF from spinal canal, needle puncture between 3rd and 4th lumbar vertebrae

14. Cerebrum Largest part of the brain
Divided into right and left hemispheres by deep groove (longitudinal fissure)
Convolutions- elevated folds on the surface of the cerebrum, they increase the surface area of the brain
Sulci- fissures or grooves separating cerebral convolutions
Divided into four lobes- frontal, parietal, occipital, temporal
Cerebral function: conscious thought, judgment, memory, reasoning, and will power.

15. Diencephalon Located between cerebrum and brain stem
Composed of thalamus and hypothalamus
Vital functions of the hypothalamus:
1. Autonomic nervous control
2. Temperature control
3. Appetite control
4. Emotional state
5. Sleep control

16. Cerebellum Located behind the pons and below the cerebrum
Composed of two hemispheres
Controls all body functions related to skeletal muscles, including:
1. Balance
2. Muscle tone
3. Coordination of muscle movements

17. Spinal Cord

18. Label the function of the brain and color the lobes!
Color pencils up front if needed
If you have your interim report SIGNED – Place in Assignment the beginning of class.

19. Brain Stem Made up of pons, medulla, and midbrain
Pathway for ascending and descending tracts of nerves
Pons- in front of cerebellum, between midbrain and medulla- contains center that controls respiration
Midbrain- on top of brain stem- controls vision and hearing
Medulla oblongata- bulb-shaped structure between pons and spinal cord- controls heart rate and blood pressure
Brain Stem

20. Spinal Cord
Begins at base of brain stem and continues down to 2nd lumbar vertebrae
White and soft, in spinal canal
Surrounded by cerebrospinal fluid
Functions as:
1. Reflex center
2. Conduction pathway to and from the brain

21. Peripheral Nervous System
All of the nerves in the body outside the CNS
Autonomic nervous system is specialized part of PNS
Nerves
Bundle of nerve fibers (ganglia) enclosed by connective tissue
Sensory nerves carry impulses to brain and spinal cord (afferent)
Motor nerves carry impulses to muscles or glands (efferent)
Mixed nerves contain both sensory and motor fibers

22. Be sure to use Roman Numerals
page 161 – complete the Cranial Nerve Box on the back of your brain diagram
Be sure to use Roman Numerals
Cranial Nerves
12 pairs
Begin in the brain
Designated by number and name
Regulate activities of the head and neck

23. Spinal Nerves
Originate at spinal cord and go through openings in vertebrae
31 pairs of spinal nerves
All are mixed nerves
Named in relation to their location on the spinal cord

24. Autonomic Nervous System
Regulates activities of visceral organs
Not subject to conscious control
Sympathetic nervous system- the “fight or flight” system- when the body perceives danger, SNS sends message to the adrenal gland (located on the kidney) to secrete adrenaline- heartbeat increases
Parasympathetic nervous system- counters effects of SNS, decreases heart rate

26. Structures of the central nervous system Autonomic nervous system
Sympathetic nervous system
Extends from the base of the brain, along both sides of the spinal column
These nerves connect to all internal organs
Parasympathetic nervous system
The vagus nerve connects the medulla with organs of the upper body
The pelvic nerve emerges from the spinal cord and connects with the organs of the lower body
3.01 Remember the structures of the nervous system

27. Structures of the central nervous system Somatic nervous system
These nerves are located along the spinal cord.
Connect skeleton, muscles and joints to the brain.
3.01 Remember the structures of the nervous system

28. Reflex Unconscious and involuntary
In a simple reflex, only a sensory nerve and motor nerve involved- example, “knee jerk” reflex