Ch 2- The Nervous System And Homeostasis Flashcards Preview

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Flashcards in Ch 2- The Nervous System And Homeostasis Deck (57):
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The nervous system

Continuous adjustment to the outside world

1

4 major functions of the nervous system

Orientation
Coordination
Assimilation
Instinctive acts

2

Orientation

To the external environment through the use of senses

3

Coordination

Dexterity through the use of voluntary muscles

4

Assimilation

Learning (speed reading)

5

Instinctive acts

Social interactions, survival, love

6

Facts about the brain

Weighs about 1.2 kg
Requires 20% of oxygen used
20% of blood your heart pumps
No sensation of pain

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Two major divisions

Central nervous system (CNS)
Peripheral nervous system (PNS)

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Central nervous system

Contains the brain and the spinal cord. (Involuntary)

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Peripheral nervous system (PNS)

All other nerves in the body

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Neurons

Nerve cell (only carry info one way)

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Cells that conduct nerve impulses are called

Neurons

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3 types of specialized neurones

Sensory neurons
Motor neurons
Inter neutron

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Sensory neurons

Carry information towards the CNS from the environment

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Motor neurons

Carry impulses from the CNS to the body, telling muscles or effectors to react

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Interneuron

Relay impulses in-between sensory and motor neurons. Found in the spinal cord

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Dendrites

Receive info from the environment or from other neurones and send an Impulse on the cell body of the neuron

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Cell body

Contains the nucleus and other organelles

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Axon

Extensions of cytoplasm that carry nerve impulses away from the cell body

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Myelin sheath

Insulated covering over the axon of a neuron

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Nodes of ranvier

Regularly occurring gaps between sections of myelin sheath along the axon

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Schwann cell

Special type of cells that produce myelin sheath

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Neurilemma

Delicate membrane that surrounds the axon of some nerve cells, promotes nerve regeneration

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Synapses

Small spaces between neurons or between neurons and effectors

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End plate

The end opposite the dendrites is called the end plate of the axon, this is where neurotransmitter are released

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Acetylcholine

A neurotransmitter making the postsynaptic neuron more permeable to Na+
Ex. Norepinephrine

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Cholinesteerage

An enzyme that breaks down acetylcholine, closing the sodium channels. Released from the dendrite end.

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Neural circuits

Reflex arc. Controls reflexes, this occurs without the brain involvement. But the brain knows what is happening

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5 essential parts to a reflex arc

Receptor
Sensory Neuron
InterNeuron
Motor Neuron
Effector

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Receptor

Part of the body that receives the stimulus, there are many type.
Ex. Temp, Presser, Chemical, Photo(light)

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Sensory Neuron

Carry messages from the body to the brain

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Interneuron

Within the spinal cord, relays between the sensory and motor neurons. Somewhat gauging if the impulse is an emergency or not

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Motor Neuron

Carries messages from the CNS to the body

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Effector

Carry out the action required, effectors are usually muscles

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Neuron

Can't reproduce because there so specialized
Self propagating system

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The synapse process

1. Acetylcholine from pre (axon end)
2. Acetylcholine crosses gap, opens Na+ doors
3. Floating Na+ enters (Neuron fires)
4. Esterase close doors (breaks connection)

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The bridge that is constructed between the synapse is made by________
The bridge is Brocken by________

Acetylcholine
Acetylcholinesterase (cholinesterase)

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Autonomic nervous system

Involuntary

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Responsible for stressfull situations

Sympathetic nervous system

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Responsible for returning the body back to normal state after a stressful situation

Parasympathetic nervous system

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Central nervous system consists of

The brain and spinal cord

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Meninges

Protective coverings around brain and spinal cord

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Cerebrospinal fluid

Shock absorber
Carrying nutrients

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Spinal cord contains the

Reflex arc -used in emergency situations

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Cerebrum

Frontal lobe
Temporal lobe
Parietal lobe
Occipital lobe
Corpus callousm connects l+r cerebrum

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Frontal lobe

Motor areas control voluntary muscles

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Temporal lobe

Sensory areas of hearing and smell

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Parietal lobe

Sensory info of touch, taste some memory

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Occipital lobe

Vision

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Medulla oblongata

Breathing/heart rate

50

Cerebellum

Coordination (dexterity)/balance
Pons- connects l+r cerebellum

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Cerebrum

Many functions
Memory's
Speech
thinking
voluntary movements
Vv

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Hypothalamus

Tell pituitary what to do
-temp, sleep, hunger.

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Pituitary gland

Controls many other glands of the body

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12 cranial nerves (need to know 4)

Vagus- heart rate
Phrenic-lung rate
Olfactory-smell
Optic-sight

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Natural painkillers

Endorphins

56

Opiates

Heroin, codeine, and morphine