1. Nervous System
Use your gray matter!

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

3. Neuron - Nerve Cell Transmits a message from one cell to the next
Has a nucleus, cytoplasm, and cell membrane.

4. Dendrites Nerve cell processes that carry impulse to cell body
May be one or many

5. Axon
Carries impulse away from cell body
Only one on a neuron

6. Neuroilemma (Myelin Sheath)
Covering that speeds up the nerve impulse along the axon
Myelin is a fatty substance that protects the axon
Synapse- space between neurons, messages go from one cell to the next

7. Different Neurons Sensory Neurons Afferent- Motor Neurons Efferent
Associative Neurons
Interneurons
Emerge from the skin or sense organs, carry impulses to spinal cord and brain
Carry messages from the brain and spinal cord to muscles and glands
Carry impulses from sensory neurons to motor neurons

8. 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.

9. Divisions of the Nervous System
Central Nervous System
Peripheral Nervous system
Autonomic Nervous System
Sympathetic/
parasympathetic
Brain and spinal cord
Cranial nerves and Spinal nerves
Includes peripheral nerves and ganglia, supplies heart muscle, smooth muscle and secretory glands, involuntary action

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

11. Coverings of the Brain (Meninges)
Dura Mater- outer brain covering, lines the inside of the skull, tough dense fibrous connective tissue.
Arachnoid-middle layer, resembles fine cobweb,
Pia Mater- covers the brain’s surface, comprised of blood vessels held together by connective tissue.

12. Subarachnoid Space
Between arachnoid and pia mater. Filled with cerebrospinal fluid- acts as a liquid shock absorber and source of nutrients for the brain.

13. Subdural space
The narrow space between the dura mater and the arachnoid membrane.

14. Ventricles of the Brain
four cavities filled with CSF 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 pons and medulla oblongota

15. Choroid Plexus
Network of blood vessels lining the ventricles which helps in the formation of cerebrospinal fluid.

16. Cerebrospinal Fluid 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.

17. Lumbar Puncture
Removal of CSF from spinal canal, needle puncture between 3rd and 4th lumbar vertebrae.

18. Cerebrum Largest part of the brain
Cerebral Function- conscious thought, judgment, memory, reasoning, and will power
Largest part of the brain
Divided into R and L hemispheres by deep groove (longitudinal fissure)
Convolutions- elevated folds on the surface of the cerebrum, they increase the surface area of the brain
Sulci- fissure or grooves separating cerebral convolutions.
Divided into four lobes- Frontal, Parietal, Occipital, and Temporal

19. Diencephalon Located between cerebrum and midbrain
Composed of Thalamus and Hypothalamus
Vital functions of the hypothalamus:
Autonomic nervous control
Temperature control
Appetite control
Emotional state
Sleep control

20. Limbic System The part of the brain associated with emotional control.
Hippocampal gyri helps to store and retain short term memory
Includes the hypothalamus – whichis considered the brain of the brain

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

22. Brain Stem Made up of Pons, medulla and midbrain
Pathway for ascending and descending tracts
Pons – in front of cerebellum, between midbrain and medulla- contains center that controls respiration
Midbrain- vision and hearing
Medulla oblongota- bulb shaped structure between pons and spinal cord, inside the cranium above foramen magnum. Responsible for :
Heart rate
Blood pressure

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

24. Peripheral Nervous System
All of the nerves of the body and ganglia
Autonomic nervous system is a specialized part of the PNS

27. Divisions of the Nervous System

28. Somatic Nervous System
part of the peripheral nervous system
responsible for carrying motor and sensory
information both to and from the CNS
made up of nerves that connect to the skin, sensory
organs and all skeletal muscles
responsible for nearly all voluntary muscle
movements as well as for processing sensory
information that arrives via external stimuli
including hearing, touch and sight.
Greek word soma, which means "body."

29. Nervous Tissue Bundle of nerve fibers enclosed by connective tissue.
Sensory nerves- (afferent) carry impulses from skin and sense organs to spinal cord and brain.
Motor neurons – (efferent) carry messages from brain and spinal cord to muscles and glands.
Associative Neurons (interneuron's) – carry impulses from sensory neurons to motor neurons

31. Cranial Nerves 12 pairs Begin in the brain
Designated by number and name

34. 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.

35. Autonomic Nervous System
Regulates activities of visceral organs
Not subject to conscious control

36. SNS and PNS Sympathetic Parasympathetic
“fight or flight” system when the body perceives danger, SNS sends a message to adrenal medulla to secrete adrenaline heartbeat increases.
Parasympathetic
counters effect of SNS decreases heart rate

37. Definitions Reflex-unconscious and involuntary
In a simple reflex, only a sensory nerve and motor nerve involved
Example: “Knee-jerk” reflex
using a reflex hammer tap the patellar tendon (on knee) what happens?