IA Study Session 6

IA Study Session 6
By David Delano

.What you need to know:
1. CNS
- Composed of the BRAIN and SPINAL cord

2. PNS
- Composed of the NERVES and GANGLIA

​

TWO SUBDIVISIONS

Fill in the Blank

In what subdivision would you find the spinal cord?

Fill in the Blank

In what division would you find ganglias?

Fill in the Blank

In what division would you find the brain?

What you need to know:
- 1 ) Visceral- INVOLUNTARY
- Visceral Motor - Ex. glands, cardiac muscle, smooth muscle
- Visceral Sensory - Ex. Lungs, Heart, Stomach

- 2) Somatic - VOLUNTARY
- Somatic Motor - Ex. Skeletal muscle
- Somatic Sensory - Ex. Skin, bones, joints, muscles

SENSORY --> AFFERENT --> ARRIVING in the CNS
MOTOR --> EFFERENT --> EXITING the CNS.

RULE BREAKER:
-Reflexes
- Technically INVOLUNTARY but can involve muscles that we can VOLUNTARY control.

Functional DIFFERENCE between subdivisions

Fill in the Blank

What division of the PNS, is known for mechanical movement of the body?

Fill in the Blank

When referring to the sub-divisons of the PNS, what word do we use to categorize something as "involuntary"

Multiple Choice

The brain sends a signal to the stomach to contract its muscle for digestion. What division is being used?

• Visceral Sensory

• Somatic Motor

• Visceral Motor

• Somatic Sensory

Multiple Choice

You step on a Lego and feel a sharp pain sensation. What division is being used?

• Visceral Motor

• Somatic Motor.

• Visceral Sensory

• Somatic Sensory

Multiple Choice

What neuronal signal ARRIVES at the CNS?

• Sensory

• Motor

What you need to know:
- 1) Sensory Neurons
- sends INFO to CNS

- 2) Interneurons = 90% of neurons
- Lie WITHIN the CNS
- Bridge the two neurons.

- 3) Motor Neurons​
- Receives INFO from CNS
- Muscles and glands act on signal

Functional Classes

Multiple Choice

What type of neuron acts on the muscles and glands?

• Sensory neuron

• Internuerons

• Motor neurons

Multiple Choice

What type of neuron bridges the gap for communication?

• Motor neuron

• Sensory neuron

• Interneuron

What you need to know:
- Dendrites - MAIN site for signal acceptance.
- Axon Hillock- Axon originates; Electrical signal is produced.
- ​Axon Terminal- Where the neurotransmitters are found.
- communicate with other neurons.
- Myelin Sheath- insulation around axon.
- Helps signal travel faster.
- Nodes of Ranvier- Small gaps between myelin sheath.
Help by allowing signal to "JUMP" from one gap to the next one.

Typical Structure of a Neuron

Multiple Choice

What structural part of the neuron does the electrical signal originate from?

• Dendrites

• Soma

• Axon Hillock

• Axon Terminal

Multiple Choice

What structural part of the neuron receives signals from another neuronal cell?

• Axon terminal

• Node of ranvier

• Axon hillock

• Dendrites

Multiple Choice

What structural part of the neuron is the small gap that helps the signal "JUMP" ?

• Axon terminal

• Node of Ranvier

• Dendrites

• Axon hillock

What you need to know:

​- Glial cells SUPPORT neurons. They protect, provide nutrients, clean waste, and help repair injuries.
1) Oligodendrocytes- Makes MYELIN in CNS.
- Myelinates MULTIPLE
2) Ependymal Cells- Secretes and circulates CSF.
3) Microglia- Defends and Disposes.
4) Astrocytes- Support and Nourishment.


1) Schwann Cells- Makes MYELIN in PNS
- myelinates ONE.
2) Satellite Cells- Support and Nourishment.

6 Types of Glial Cells

Multiple Choice

What glial cell is responsible for myelination in the CNS?

• Astrocytes

• Oligodendrocytes

• Schwann Cells

• Satellite Cells

Multiple Choice

What glial cell is responsible for defense and disposal in the CNS?

• Oligodendrocytes

• Satellite Cell

• Schwann Cell

• Microglia

Multiple Choice

What glial cell is responsible for support and nourishment in the CNS?

• Astrocytes

• Oligodendrocytes

• Schwann Cells

• Satellite Cells

Multiple Choice

What glial cell is responsible for myelination in the PNS?

• Oligodendrocytes

• Astrocytes

• Microglia

• Schwann Cells

Signal depends on DIAMETER and PRESENCE/ABSENCE of myelin!

What you need to know:
- Myelinated- Signal is FASTER; it "JUMPS"
-SALTATORY Conduction

- Unmyelinated- Signal is SLOWER; "Gradual"

​ - Continuous Conduction

Myelinated vs. Unmyelinated

What you need to know:
- Presynaptic Neuron - Nerve that SENDS the signal
- Synapse- The CONNECTION POINT of TWO cells.
- Postsynaptic Neuron - Never that RECEIVES the signal.
- Synaptic Vesicle- Tiny sacs that hold NT.
- Neurotransmitters (NT) - Chemical messengers that carry SIGNAL ACROSS the synaptic cleft.
- Synaptic Cleft- SMALL gap between pre- and post-synaptic neurons.

​

Synapses/Synaptic Junctions

What you need to know:
- Chemical - Sends NT signal
- Has a SYNAPTIC CLEFT
- Depending on NT can excite/inhibit.

-Electrical - Diffusion of IONS.
- Is joined by GAP JUNCTIONS.
- NO DELAY of NT release/binding

Electrical vs. Chemical Synapses