Nervous System

Question 1

What is the organization of the nervous system? Functions?

Answer 1

Central Nervous System (CNS): Brain, spine, spinal cord. Receives, processes, responds sensory information, sensation, movement, emotion, memory, thought, communication, processing unit, high and fine motor

Peripheral Nervous system (PNS):
Nerves throughout the body, neural tissue

Question 2

What are the two subdivisions of PNS? What are the two subdivisions of those two?

Answer 2

Sensory (afferent): Incoming messages
Somatic sensory division: Muscle/skin
Visceral sensory division: Organs

Motor (efferent): Outgoing command
Somatic (voluntary) motor division
Autonomic (involuntary) motor division (heart rate, breathing)

Question 3

What is the subdivision of Autonomic motor division (involuntary)? What do they do?

Answer 3

Sympathetic: Increased body rate e.g. anxious or stressed

Parasympathetic: Decrease body rate, relaxation

Helps to speed up or slow down breathing, digestion, blood vessels constrict or dilate

Question 4

Cells of the nervous system:

Answer 4

(Neuro) Glial cells: Support, nourish and protect, 90% of cells in the nervous system. e.g. astrocytes, microglia/satellite cells, ependymal cells, oligodendrocytes, Schwann cells

Neurons: Main function of the cell, 10% of cells in the nervous system, unable to regenerate so does not create more but makes ones that are better

Question 5

What is the neurons function?
What parts make up the neuron?

Answer 5

Central communication tool, main functional unit of NS. Sending and receiving impulses. They all connect and deliver information.

Parts:
Dendrites
Cell Body
Nucleus
Axon
Terminal Axon
Myelin sheath - covers axon of some neurons and helps speed neural impulses

Dendrites receive information, goes through the cell body, travels along the axon to terminal branches where it can connect with other neurons

Question 6

Structural classifications of neurons?

Answer 6

Unipolar: A single process extending from the cell body (sensory neurons). The cell body is located off to the side and extends into two opposite directions

Bipolar: Two processes extending from the cell body (axon and dendrite), sensory and interneurons. Most rare but found in the olfactory and retina of the eye.

Pseudo unipolar: Interneurons, sensory neurons

Multipolar: Multiple processes extending from the cell body, motor sensory and interneurons. Comprise of 99% of neurons in the body

Question 7

Action potentials and communication:

Answer 7

Membrane potential is defined as the difference in charge between the intracellular environment of a cell. The neuron has ion gated channels, ion leakage channels and active ion pumps in the plasma membrane that alter/adjust the charge mV of the membrane which alters the membrane potentials. To have an impulse or action potential, it changes the charge

Question 8

Changes in membrane potential:

Answer 8

Voltage-gated channel: respond to changes in electrical charge (active transport of sodium or potassium)

Leakage channels: Always open or leaking, flows with the concentration gradient (passive transport)

Sodium-potassium pump: Uses ATP to continuously pump ions against the concentration gradient, active transport

Question 9

Action potentials?

Answer 9

Occur as a result of rapid change in the membrane potential, electrical impulse is generated in response to specific changes in the activity of the ion gated channels/leakage channels/pumps

Question 10

How do cells talk to each other?

Answer 10

Synaptic transmission
Neurotransmitters flood into the synapse, they reach across to a new neuron and land on a receptor to receive it to do something which starts its own neuron potential

Question 11

Inhibitory vs excitatory neurotransmitters

Answer 11

Inhibitory - Block or prevent the chemical message from being passed along any further. Most in CNS are inhibitory we only want to control commands for a number of different things (e.g. serotonin regulates mood, GABA, glycine)

Excitatory- Excite the neuron and causes it to fire off the message so it can be passed on to the next cell e.g. glutamate which increases memory, cognition and mood. e.g. glumate, epinephrine, norepinephrine

Epilepsy sends so many conflicting commands as there is an imbalance of neurotransmitters which causes seizure

Question 12

What are examples of neurotransmitters?

Answer 12

Adrenaline, Noradrenaline, Acetylcholine, Gamma-Aminobutyric Acid (GABA), Serotonin, Dopamine

Question 13

Brain Matter

Answer 13

Gray matter: Neuron cell bodies, dendrites and unmyelinated axons

White matter: Bundles of myelinated axons, fast transmission (to make things go off quickly in the brain), Myeline sheath of the neuron is white matter

Question 14

What are the 4 anatomical divisions of the brain?

Answer 14

Cerebrum, Diencephalon, Brain Stem, Cerebellum

Question 15

Functions and Anatomy:
Cerebrum and Diencephalon

Answer 15

Cerebrum: Left and Right hemispheres, Left controls RHS of the body, right hemisphere controls LHS of the body. People who are deaf have issues with Wernicke’s or Broca’s area so have impaired speech

Diencephalon: Thalamus- relay station, crossover area and the last point of the neuron coming up our spinal cord. Responsible for relaying information to and from the cerebral cortex, responsible for level of consciousness

Question 16

Function and Anatomy:
Brain Stem and Cerebellum

Answer 16

Brain stem:
Mid brain
Pons - Reticular Activating System = Sleep/ Wake cycles
Breathing, heartbeat, blood pressure

Cerebellum:
Responsible for balance
Head injuries that effected cerebellum can’t balance
Proprioception - knowing where you are in a time and place

Question 17

Cerebrum process and response:

Answer 17

Frontal lobe: Personality, thinking, planning, organizing, problem solving, emotions, decision making

Temporal Lobe: Wernickes Area, around ears, needed for memory, understanding language, facial recognition, hearing, speech, emotion

Parietal lobe: Perception, object classification, spelling, arithmetic, visuospatial processing

Occipital lobe: Vision, visual processing, color identification, balance

Cerebellum: Gross and finer motor skills, hand eye coordination, balance

Brain Stem: Regulates body temperature, heart rate, swallowing and breathing

Parietal region: Somatosensory cortexq

Question 18

Meninges of the brain:

Answer 18

Layers and sub-layers of the brain, highly vascular, meningitis is inflammation - build up of pressure to stop the brain from working well

Question 19

What is the spinal cord?

Answer 19

Column of nervous tissue that connects the brain and PNS. Forms a two way communication pathway and conducts signaling between the brain and the rest of the body.

Contains 4 different regions that correspond to the areas of the body; Cervical, thoracis, lumbar, sacral

Question 20

Spinal Nerves: PNS

Answer 20

Anterior/Ventral roots contain motor neurons (information going out from CNS to PNS effector muscles)

Posterior/ Dorsal roots contain sensory neurons (information coming in from PNS (sensory receptor) to CNS)

Spinal nerves from where the anterior and posterior roots come together as they exit the spinal cord (both motor and sensory neurons)

Sensory pathway - ascending
Motor pathway - Descending

Question 21

What are sensory receptors?
What are the 5 types?

Answer 21

Sensory Receptors are sensory nerves that carry information from the body (PNS) to CNS via sensory receptions

Thermoreceptors: Detect temperature

Mechanoreceptors: Detect touch, pressure, vibration

Chemoreceptors: Detect chemical stimuli

Photoreceptors: Detect light

Nociceptors: Detect Pain

Question 22

What are spinal nerves?

Answer 22

Bundles of nerve fibers that are connected to the spinal cord and are mixed at sending both sensory, motor and autonomic signals. If they are damaged we will lose control of body parts

Question 23

Where is the myelin sheath found?

Answer 23

The CNS

Question 24

How are neurons structured?

Answer 24

The are all multipolar