Lecture Notes: Chapters 7-9 Nervous System

Front 1

Afferent Pathways

Back 1

Sensory function: sense changes in internal or external environment via sensory receptors.

(Sensory neurons)

Front 2

Efferent Pathways

Back 2

Respond to stimuli. Consist of motor neurons.

Front 3

CNS

Back 3

Central Nervous System: Includes the Brain, and Spinal Cord

Front 4

PNS

Back 4

Peripheral Nervous System: Includes the Cranial Nerves, Spinal Nerves, Ganglia, Enteric plextures in small intestine, and Sensory receptors in the skin.

Front 5

Autonomic Nervous System (PNS)

Back 5

Involuntary; to and from glands, smooth muscle, and cardiac muscle.

Front 6

Enteric Nervous System (PNS)

Back 6

Involuntary; nervous system of GI tract

Front 7

Neurons / Nerve cells

Back 7

Information transfer, able to respond to stimuli, have long processes to transmit impulses over long distances.

Front 8

Structure of Neurons

Back 8

1. Cell body

2. Dendrites

3. Axons (axon hillock, axon terminal, synaptic end bulb)

Front 9

Neuron vs. Nerve

Back 9

1. Neuron = one single nerve cell / axon

vs

2. Nerve = group of neurons / axons

Front 10

Ulnar Nerve

Back 10

"Funny bone"

Front 11

Myelin

Back 11

In PNS: Schwann cells

In CNS: Oligodenrocyte

Myelin sheath "insulates" axons so that nerve impulses can leap across the neuron which increases the speed of conduction

Front 12

Nodes of Ranvier

Back 12

Little gaps in the myelin sheath where the axonal membrane is exposed.

Allows for saltatroy conduction (jumping).

Front 13

Oligodendrocytes

Back 13

Each oligodendrocyte has many processesthat are sent out to the axons of nearby neurons which they wrap themselves around to create a myelin sheath

Front 14

Demyelination

Back 14

Loss or destruction of myelin sheath around neurons in CNS. MS is an example.

Front 15

Resting Membrane Potential

Back 15

Abbreviated Vm, the resting potential in the neuron is -70mV.

Front 16

Sodium-Potassium ATPase

Back 16

A form of active transport that requires ATP. It pumps Sodium ions out of the cell and pumps potassium ions into the cell.

Front 17

Action Potential

Back 17

Caused by the concentration difference from the ECF to the ICF (Na Ions and K Ions). There is a higher concentration of sodium ions in the ECF and a higher potassium concentration in the ICF. Depolarization (more Na coming into the cell) causes the resting potential of -70mV to increase to +40mV via a chain reaction, spreading down the axon. Once +40mV has been reached, the Na pumps will close and the K pumps will open to create equilibrium again. This begins the process of re-polarization and eventually leads back to the resting potential (-70mV).

Front 18

Continuous Conduction vs. Saltatory (leaping) Conduction

Back 18

Continuous conduction is caused by current flow from opening Na channels and the chain reactions without jumping.

Saltatory occurs with jumping from node to node around the Schwann cells.

Front 19

Components of Synapse

Back 19

1. Axon terminal of pre-synaptic neuron

2. Synaptic cleft (space between cells)

3. Membrane of post-synaptic cell (dendrites, muscle cell)

Front 20

Cerebral Cortex

Back 20

A layer of gray matter forming the outer rim of the cerebrum (gray surrounds with folds on the cerebrum)

Front 21

Cerebral Cortex Components

Back 21

1. Gyrus (gyri): Elevated ridge of tissue gray in colour, contains cell bodies and dendrites (the very most outside part of the cerebral cortex)

2. Sulcus (sulci): little folds within the cortex

3. Fissure: the large fold down the center of the cerebral cortex separating the sides.

Front 22

Functional ares of the Cerebral Cortex

Back 22

1. Sensory Areas (involved in perception of sensory information)

2. Motor areas (control execution of voluntary movements)

3. Association areas (integrate information, form thoughts and relay decisions)

Front 23

Sensory areas

Back 23

Sensory areas:

a. Primary Somatosensory Area: Receives info for touch, pressure, vibration, itch, tickle, coldness, warmth, pain, proprioception. Involved in the perception of these sensations.

b. Primary Gustatory area: receives info for taste, involved in gustatory perception and taste discrimination

c. Primary visual area: receives info for vision, involved in visual perception

d. primary auditory area: recieves info for sound, involved in auditory perception

e. Olfactory bulb, olfactory tract, primary olfactory cortex

Front 24

Motor areas

Back 24

Motor areas:

a. Primary motor area: controls voluntary muscle contractions related to skilled complex or delicate movement --> motor homonculus

b. Broca's speech area: language center speaking the thoughts, controls and coordinates larynx, pharynx and mouth muscles and breathing muscles. Dominant in the left hemisphere

Front 25

Association areas

Back 25

1. Somatosensory association area: Receives info from the primary somatosensory area, the thalamus and other cerebral areas. Determines object's shape, orientation and stores memories.

2. Visual association area: Receives information from the primary visual areas and the thalamus. relates the previous visual experiences to interpret current visual stimuli and recognizes faces, words objects and spatial relationships.

3. Auditory association area: Receives information from the primary auditory area, permits the perception of sound stimuli and stores memories of sounds heard in the past for reference.