Neurology: Physiology-Unit 4

Nervous System Functions (3)

• Sends & receives messages

• Detects stimuli

• Controls all bodily activities.

Nervous Systems Organs (4)

• Brain

• Spinal Cord

• Nerves

• Neurons

Nervous System Divisions (2)

1. Central Nervous System (CNS):

2. Peripheral Nervous System (PNS):

Nervous Tissue Group

N

Nervous Tissue Function

Receives neurotransmitters & sends impulses within body.

Nervous Tissue Specialized Cell

Neurons

Central Nervous System

Central Nervous System includes (2)

• Brain

• Spinal Cord

Peripheral Nervous System

Peripheral Nervous System Includes (1)

Nerves

Central Nervous System (CNS) includes: (2)

Brain & Spinal Cord

Peripheral Nervous System (PNS) includes:

5 Senses (nerves that extend from CNS)

Stimulus

Something that causes a person to respond (can be internal or external)

Response

An action taken

Reflex (4)

• Involuntary (autonomic)

• Processed by spinal cord

• Quick, defense mechanism

• Ex: touching a hot stove or shivering (response to temp)

Reaction (4)

• Voluntary (somatic)

• Processed by brain

• Complex response

• Ex: swinging a bat

Reflex Arc (3)

• Neurons send signal that skin made contact with fire.

• SPINAL CORD processes info

• Neurons tell muscles in hand/arm to move away

Reaction (3)

• Neurons send signal that there is a ball to hit.

• BRAIN processes info.

• Neurons tell muscles to contract in hand to click & swing bat

Sensory Neuron Function

DETECTS change in stimulus & CARRIES INFO TOWARD interneuron.

Sensory Neuron Location

Along all 5 senses (within skin, tongue, nose & behind eyes, ears).

Interneuron Function

PROCESSES INFO received from sensory neurons.

Interneuron Location (2)

• Brain

• Spinal Cord

Motor Neuron Function (2)

• Make muscles contract/ relax.

• Performs job interneurons command

Motor Neuron Location

On/over muscles.

Cell Body

Dendrite

Receptor Protein

Nucleus

Axon

Myelin Sheath

Axon Terminal Branch

Neurotransmitter

Vesicle

Synapse

Cell Body Function

Carries out life activities

Dendrite Function

Receives chemical signals

Receptor Protein Function

Attaches to chemical signal molecules

Nucleus Function

Controls life activities

Axon Function

Conducts electrical signals called impulses, over long distances.

Myelin Sheath Function

Insulates Neuron & speeds up impulse conduction (surrounds axon)

Axon Terminal Branch Function

Sends message to next neuron

Neurotransmitter Function

Chemical message (dopamine, etc)

Vesicle Function

Stores & release neurotransmitters

Synapse Function

Gap between two neurons

Nervous System is divided into (2)

• Central Nervous System

• Peripheral Nervous System

Central Nervous System Uses (1)

Interneurons

Interneurons include

Include Brain & Spinal Cord

Peripheral Nervous System Uses (2)

• Sensory Neurons

• Motor Neurons

Motor Neurons can be used in (2)

• Involuntary: Autonomic N.S.

• Voluntary: Somatic N.S.

Autonomic N.S. is ____&____ muscle

• Cardiac muscle

• Smooth muscle

Somatic N.S. is ___ muscle

Skeletal Muscle

Concussions aka

Traumatic Brain Injury (TBI)

What happens to brain during concussion

Brain hits skull abruptly.

How one can get a concussion

Generally only event where your body stops abruptly (falling, accidents, sport).

Prevention method to concussion

Generally anything would prevent an accident & help cushion your brain on impact (helmets, etc).

Immediate symptoms of concussion (3)

1. Confusion

2. Vomiting

3. Nausea

There is ___ on brain after impact

Swelling

Treatment for concussion (4)

1. Rest

2. Limiting Screen time

3. Break from homework/ critical thinking

4. Eating healthy during recovery.

REST (2)

• Minimizes swelling

• Gives opportunity for stretching to heal

Limiting Screen Time & Break from homework/ critical thinking both

Limit “firing” of neurons

Eating healthy during recovery

Replenishes fuel that is missing from brain to make ATP.

Breaking axon (2)

• Permanent damage

• Axons cannot send info at all.

Stretching Axon (2)

• Temporary damage

• Axons cannot send info while swollen

Both stretching or breaking of axon can cause a ____________ &_______

• Leakage of proteins in brain.

• Destabilizes Neuron cells.

Action Potential

Electrical impulse that triggers a change in charge across the axon membrane.

Rested Axon

Negative inside membrane, positive outside.

Stimulated Axon

Positive inside membrane, negative outside.

Arrow of neuron represents

Direction of impulse / action potential.

Steps of Communication within a Neuron (4)

1. Neuron AT REST

2. A message is received from another neuron

3. The ACTION POTENTIAL

4. When the axon is DONE sending a signal.

1. Neuron at Rest (2)

• Not sending any messages

• Has a negative charge inside and a positive charge outside the Neuron.

2. A message is received from another neuron

An electrical signal called an impulse or action potential travels along the axon of a neuron.

3. The ACTION POTENTIAL (2)

• Temporarily causes the charges to change.

• There is a positive charge inside & a negative charge outside the neuron.

4. When the axon is DONE sending a signal (2)

• Will return to its resting phase

• Now ready to send another signal

Neuron at Rest visual

Message received from another neuron visual

Action potential visual

When axon is DONE sending signal visual

(last step)

Focal

One part of brain

Generalized

All over brain

Immediate symptoms of seizures (3)

1. Jerking movements of arms & legs.

2. Staring into space

3. Loss of consciousness

Common causes/triggers of seizures (4)

1. Fever/ infection

2. Having a stroke

3. Head injury

4. Epilepsy

Treatment: Medication

Sedative drugs can calm overactive neurons.

Seizure First Aid (3)

1. Keep person safe from falling

2. Shift on side to keep airways open.

3. Stay with them until help arrives.

Concussion causes (2)

1. Torn axon

   OR

2. Axon bubbles up.

Seizure causes (2)

1. Sustained neuron firing

   AND

2. Shortened rest periods.

Neuron Error 1: Misfiring Neurons (2)

• Neurons fire out of sequencing.

• Info not received so that it is understood.

Neuron Error 2: Excess Electrical Activity (3)

• Neuron = continually firing.

• Overstimulation of info

• Neuron cannot relax between signals.

Diffusion

Surrounding cells absorb excess NT.

Reuptake

Transporter proteins in axon terminal remove NT.

Degradation

Enzymes in synapse break down NT so they lose function

Substance (Drugs/Alcohol) Effects (3)

1. MIMIC

2. BLOCK

3. Increase Production (of neurotransmitter in synapse)

Dopamine Function & Drug that affects in (2)

• Pleasure/ reward system

• Cocaine

Serotonin Function & Drug that affects in (2)

• Regulates mood (happiness)

• Ecstasy

Endorphins Function & Drug that affects in (2)

• Natural painkillers, sedation

• Heroin

GABA Function & Drug that affects in (2)

• Blocks impulses

• Alcohol

Acetylcholine Function & Drug that affects in (2)

• Muscle contraction, memory centers

• Nicotine

Anandamide Function & Drug that affects in (2)

• Regulates appetite, sense of time & short term memory.

• Marijuana / THC

Transporter Proteins

Take up excess neurotransmitters from synapse

Inhibitory ____,____,____ impulses of neuron

• Block

• Stop

• Slow down

Excitatory ____,____,____ impulses of neuron

• Enhance

• speed up

• increase impulses of neuron