Nervous System

Division of the Nervous system

Central Nervous System

Brain and spinal cord

Peripheral nervous System

Crainial nerves and spinal nerves

Are divided into Afferent and Efferent

Afferent Neurons

Made of Sensory Neurons

Efferent Neurons

Made of Motor Neurons

Are divided into somatic and autonomic

Somatic Nervous System

Voluntary Responses

Autonomic Nervous System

Involuntary Responses

Are divided into sympathetic and parasympathetic

Sympathetic Nervous System

Fight or Flight Response

Involve skeletal muscles

Parasympathetic Nervous System

Involved with rest and digestion

Involve cardiac muscles and glands

Neural Cells

Neurons and Glials

Types of Neurons

Inter neuron, Sensory neuron, and Motor neuron

Dendrite

Short-branched fibres that convert chemical information from other neurons or receptor cells into electrical signals

Axon

An elongated fibre that transmits electrical signals to terminal regions for communication with other neurons or effectors

Soma

A cell body containing the nucleus and organelles, where essential metabolic processes occur to maintain cell survival

Inter Neuron

Found in Central Nervous System

The link between sensory and action

^^Short^^ Dendrites

^^Short^^ Axons

Sensonry Neuron

Relay messages from receptors to Central Nervous System

^^Long^^ Dendrites

^^Short^^ Axons

Motor Neuron

Relay messages from the interneuron to the effector (muscle)

^^Short^^ Dendrites

^^Long^^ Axons

Nervous System process

Sensory input, integration, motor output

Reflex Arc

Receptor, sensory neuron, interneuron, motor neuron, effector

Cerebrum

Main part of the brain

Associated with thoughts and actions

Made of 4 lobes

Frontal Lobe

Part of the brain that deals with;

Personality

Emotions

Intelligence

Parietal Lobe

Part of the brain that deals with;

Sensations; pain, touch, temperature

Temporal Lobe

Part of the brain that deals with;

Hearing

language

Occipital Lobe

Part of the brain that deals with;

Vision

Brain Stem

Part of the brain that deals with;

Autonomic actions: breathing, heart control, swallowing, blood pressure, sweating, etc.

Cerebullum

Part of the brain that deals with;

Balance

Motor Skills

Posture

Is connected to the brain stem

Thallamus

At the top of brain stem

two lobes that relay sensory and motor messages to cerebrum

Regulation of sleep and conciousness

Hypothallamus

Below the Thallamus

Involved in homeostasis

regulated blood pressure, body temperature and water balance

Medulla Oblongata

reflex centre of the brain

swallowing, sneezing, coughing

respiration and circulation

Spinal Cord

Nerves branch out from main cord to the various parts of the body

Damage to any section will cause problems to lower sections

Potential

Difference between +/- ions between two points

Resting Potential

Neuron at rest (not sending a signal!)

More Na+ outside; more K+ inside

Caused by sodium/potassium ATP pump

Overall: mV -65

Action Potential (Depolarization)

Depolarization (upswing)

The sodium channel opens and sodium rushes in

Potential changes until the threshold is reached (-40 mV) and an all-or-nothing response occurs

Once it is reached, depolarization goes until 40mV

Action Potential (Repolarization)

Repolarization (downswing)

Sodium gate closes, Potassium gate opens and it rushes out

Potential changes until it is slightly below resting potential (-65mV)

Inside is negative compared to outside

Recovery Phase

Refractory Period

Sodium and Potassium gates close

Na/K Pump pumps K outside and Na inside

Nodes of Ranvier

Individual sections of the axon

Effeciently and quickly moves signal along

Saltatory Conjunction

The jumping of the action potential from node to node

Myelin Sheath

Insulating layer around the axon

Synaptic Transmission

Changes electrical signal (voltage) to chemical signals (neurotransmitters)

Neurotransmitters bind to dendrites to cause a new action potential

Synaptic Cleft

Between the axon and the dendrite