Day 1-3 Nervous

Central Nervous System is made up of. . .

• Brain

• Spinal cord

Peripheral Nervous System

• Nerves of the body extending to periphery

  • Cranial Nerves

  • Spinal Nerves

Afferent

Incoming Info (Sensory pathways)

Efferent

Outgoing Info (motor pathways)

PNS effectors

• Somatic- Carry information to/from skeletal mm(voluntary)

• Autonomic- Carry information to/from (smooth mm, cardiac,& glands) (involuntary functions)

  • Sympathetic- fight,flight,freeze

  • Parasympetic- Rest+Repair

Nervous System Physiology

1. Communication- controlling different functions for homeostasis

2. Feels sensation: Internal + external stimuli

3. Evaluates information

4. Organizes info for immediate use, stores info

5. Initials appropriate response (quicker than endocrine)

Two kinds of nervous system cells

1. Neuroglia

   1. mostly in CNS

   2. NO CONDUCTION

   3. supports neurons functions

   4. cells divides (can be adnorm)

   5. 5 Types

2. Neuron

1# Astrocyctes

CNS

Anatomy

• star-shaped, point attached to neurons and blood capillaries

• Most numerous cell

Physiology

• Feed neurons with nutrients from blood

• Forms blood-brain barrier

  • Only small molecules diffuse through Ex. o2,co2

• Influence growth of neurons

• transmits information on astrocytes-pathways

2# Microglia

CNS

Anatomy

• Small stationary cells

Physiology

• Enlarge in inflamed/dead tissue

• Move to phagocytize debris/microorganisms

3# Ependymal Cells

CNS
Anatomy

• Form sheets to line fluid-filled cavities in CNS

Physiology

• Choroid plexus- produces fluid that fills cavities

• some have Cilia to keep fluid flowing

4# Oligodendrocytes

CNS
Anatomy

• clustered around nerve cell bodies or arranged in rows

Physiology

• hold nerve fibers together

• produce myelin sheath in CNS

  • NO REGENERATION

5# Schwann Cells

PNS

physiology

1. Same function as oligodendrocytes

2. Supports nerve fibers

3. myelin sheath on nerve fiber

4. Schwann cells wrap around a single nerve fiber, which squeezes the cytoplasm and nucleus to form the neurolemma (so they can regeneration) w/ tunnel

5. Gaps in the myelin sheath called the nodes of Ranvier, faster jumping of impulses.

Nervous system cells- 2# Neurons

1. primary structural/function part of the nervous system

2. 100 billion neurons/900 billion neuroglia

3. capable of mitosis (prenatal only)

4. Grow in size NEVER NUMBER

Neuron : Cell body

Contains:

1. Nucleus

2. Cytoplasm

3. organelles

4. neurofibrils

   1. Structural Support/transportation system for moelcules to get from/too ends of neurons molecules

5. Rough ER

   1. Provides protein molecules needed for transmission of nerve signals and regeneration of nerve fibers

6. Close to CNS

Neuron: Axon

1. Carry impulses away from cell body

2. can be lengths/diameter

3. Axon collaterals

4. terminate in distal branches/synaptic knobs

5. could be myelinated

: Dendrites

1. Thread extension from the cell body

2. Impulses toward the cell body

3. Distal ends receive stimuli/initial nerve signals

4. NO MYELIN

1# Multipolar neurons

(efferent) (MOTOR NEURONS)
1. carry impulses from CNS to skeletal mm +smooth mm +glands

2. one axon, many dendrites

• Somatic- Skeletal mm

• Visceral- smooth, cardiac, muscle, glands

2# Bipolar Neurons

• Special Sensory Area (eye,nose,ears)

3# Unipolar Neurons

(afferent) (sensory)

1. Sensory Neuron (two branches off the cell body)

1. one branches to peripheral body as dendrite.

2. one branch to spinal cord - Axon

• somatic= skin,joints,skeletal mm

• Visceral: internal Organs

Interneurons

multipolar

• carry impulses from afferent neurons to efferent neurons

• found entirely in CNS