1. Stimulus occurs 2. Receptor detects stimulus 3. Sensory neuron sends impulse to CNS, Interneuron sends impulse to brain. 4. Brain decides on a response 5. Motor neuron sends an impulse to the effector. 6. Effector carries out response

The Nervous System Flashcards by Nola Dubuisson

difference between central nervous system and peripheral nervous system

CNS: brain and spinal cord
PNS: cells called nerves branching from CNS to all of body

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What is the nervous system responsible for

allows organisms to react correctly to stimulus in their environment so that they can survive

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Def. of stimulus

Any change in our environment

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Impulse def.

An electrical message that is carried along a nerve cell

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Receptor def.

A sense organ that detects the stimulus.

Eg. Eye, Ear, Nose

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Effector def.

Receives a message and carries out the action/ response

eg. Muscle/Gland

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Nerve cells
Function
another name
types

Function: carry impulses to and from the CNS to allow us to react correctly to stimulus
Another name: Neurons
Types:Sensory, Inter, Motor

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Sensory neuron function and other name

Function: Carries impulses from Receptor to the CNS

Another name: Afferent Neuron

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Interneuron
Function
Another name

Function:Connects sensory and motor neurons and carries messages within CNS-within brain and spinal cord to brain
Another name: Intermediate/Relay/Association

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Motor neuron
Function
Another name

Function: Carries messages from CNS to Effector

Another name: Efferent

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Process of response

Stimulus occurs
Receptor detects stimulus
Sensory neuron sends impulse to CNS, Interneuron sends impulse to brain.
Brain decides on a response
Motor neuron sends an impulse to the effector.
Effector carries out response

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Structure of a neuron

Three types

(in direction of impulse)
Receptor-Dendrites-Dendron-axon hillock-cell body(soma)-axon-axon terminal
Along dendron/axon: The myelin sheath-schwann cells. Node of Ranvier in between schwann cells
Sensory: soma/Cell body sticks up and receptor at start.
Inter: Soma is on the dendron in the middle
Motor: Soma is near dentrites-no dendron, effector at end.

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Functions of cell body

contains nucleus
makes other parts of the neuron
connects to the dentrites and passes the impulse to the axon

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Functions of dendrite

Nerve endings

connects to another neuron or receptor and receives the information/impulse

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Functions of dendron

Short fiber that receives information from the dendrite and carries it toward the cell body

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Functions of axon

carries impulses away from cell body

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Functions of axon hillock

part where cell body connects to axon

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Functions of schwann cell and myelin sheath

makes the myelin sheath which insulates and protects the neuron.

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Functions of node of ranvier

gap between each schwann cell.

speeds up the impulse

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Functions of axon terminal

release chemicals known as neurotransmitters to pass the impulse to the next neuron

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Other names for axon terminal

terminal knob,

synaptic knob

Disorder of the nervous system
Name
Causes
Symptoms
Prevention
treatment

Name: Parkinsons
Causes: Lack of dopamine (controls muscle contraction)
Symptoms: muscles become rigid, movement slow, movement difficult and painful, tremors
Prevention: no means of prevention
Treatment: giving L-dopa (converted to dopamine in body), physio, exercise with balancing and stretching, speech therapy, surgery to stimulate brain

Endocrine system vs. Nervous system
Cells involved
Message type
Carried by
Received by
Speed of transmission
Effects
Duration

Cells involved: glands-sense receptor
Message type: chemical-electrical
Carried by: blood-neuron
Received by: target organ-effector
Speed of transmission: slow-fast
Effects: widespread-localised
Duration: long lasting-brief

Structure of brain

skull
lining skull (2 parts)
big brainy thing
like a heart
smoother thing near big brain
seahorse thing-bottom (6), tummy (7),head (8)
centre of everything
dotty thing near seahorse

Cranium
Meninges and cerebro-spinal fluid
Cerebrum
Cerebellum
Corpus Callosum
Medulla oblongata
Pons
Pituitary gland
Thalamus
Hypothalamus

What are the left and right sides of the brain referred to as

Hemispheres

Function of Cerebrum

Controls language, memory, intelligence and consciousness

Function of cerebellum (bella the ballerina)

Muscle coordination, movement and balance

Function of medulla oblongata | obligated to

Controls breathing and heart rate

Function of Meninges and Cerebrospinal fluid

Protects brain | Meninges-lining of fluid

Function of Hypothalamus

secretes hormones to control the pituitary gland | near to the pituitary

Function of Corpus Callosum

Connects right and left sides/hemispheres

Function of Pituitary gland

Secretes hormones to control other glands

Function of Thalamus

Sorting centre of all the messages that the brain receives and sends the message to the correct part

Where are the following located on the cerebrum 1. intelligence, memory, consciousness, language 2. Vision 3. Smell 4. Hearing 5. Taste 6. Speech 7. Motor control 8. Sensory control

1. front 2. back (eyes at the back of the head) 3. Underneath 4. Centre 5. Centre 6. Centre 7. Top 8. Top (behind 7.) * (for 3-6 think of where they are positioned in the head)

Right hemisphere functions

Controls left side of body Art, Music etc. If strong right side often left handed

Left hemisphere

Controls right side of brain Language, Maths *right handed

Transmission of impulse from one neuron to next process

1. Pre-neuron transmits impulse 2. Impulse arrives at synaptic knob 3. Vesicles containing the impulse move to the edge of the knob 4. Vesicles open releasing neurotransmitters to carry the impulse to the post neuron 5. The neurotransmitters bind to the receptors on the post neuron 6. The impulse is generated on the post neuron and travels along the neuron.

What is the point where a pre neuron meets a post neuron called

a synapse

What is a synaptic cleft

the space between neurons in a synaps

Why are neurotransmitters needed at a synaps

Impulses are electrical and cannot cross a synaptic cleft. the impulse must be chemical to cross. neurotransmitters change the impulse to a chemical impulse

Neurotransmitters def. type of particle example

Def: Chemicals released from the pre neuron to carry the impulse to the post neuron. Released from vesicles and bind to receptors Type: Ions Examples: Dopamine, Acetylcholine, Noradrenalin

Inactivation of neurotransmitters What it is Why important

Once they have carried the impulse across the synaptic cleft they are broken down and digested by enzymes in the post neuron. they return back to vesicles on the pre neuron to be reused. Important to prevent over stimulation of the post neuron and over firing of impulses

Threshold def.

the threshold is the minimum stimulus that is required to cause an impulse to be sent. A stimulus below the threshold won't send an impulse One above will

All or nothing law

states that if the threshold is reached an impulse is carried, if the threshold is not reached an impulse will not be carried. Impulse is either carried or not.

Refractory period

The short period of time after a neuron has sent an impulse that a stimulus can cause no response on the neuron. ie. the neuron has a short rest

Importance of a synaps

Allows an impulse to be sent between neurons. It prevents the over stimulation of effectors. It controls the direction of impulses- neurotransmitters are only found in the terminal knobs

Reflex action def. examples advantages

A reflex action is a very fast unconscious, involuntary response to an unexpected stimulus Eg. Knee jerk reaction, Blinking, moving finger away from flame adv: Protects from damage

What is a reflex arc

Is a specific nerve pathway involved in this fast unconscious response to an unexpected stimulus.

Pathway of a reflex arc | and diagram

1. Receptor 2. Sensory neuron 3. Spinal cord, brain 4. Interneuron 5. Motor neuron 6. Effector Diagram: Dorsal root (enter via the door), Dorsal root ganglion, ventral root, White matter (outside), Grey Matter (inside), Neural canal (centre)

Dorsal root ganglion function

swelling in the dorsal root caused by the cell body of the sensory neuron sticking up

Spinal cord function | protected by

Function: Transmits impulses to and from the brain | Protected by: vertebrae, meninges, cerebrospinal fluid

White matter vs. Grey matter

White matter: On outside-contains axons | Grey matter: On inside- contains cell bodies and dendrites