Bio 30 Chapter 11 The Nervous And Endocrine Systems

Front 1

What is a neuron?

Back 1

it is a nerve cell specialized for conducting nerve signals over long distances.

Front 2

What is a dendrite?

Back 2

the extensions on a neuron. They receive electrochemical pulses from impulses.

Front 3

What is dendrite fibres?

Back 3

They conduct nerve impulses down the neuron towards the larger dendrite branches.

Front 4

what is dendrite knobs?

Back 4

it is located on the end of dendrite fibres. They contain receptor sites where neurotransmitters attach.

Hint 4

if the threshold level is met or surpasses it will initiate a nerve impulse starting here, by causing the Na+ (sodium) gates to open and Na+ will begin to flow into the neuron.

this will result into a chain reaction down the entire neuron.

Front 5

what is an axon?

Back 5

it carries the nerve impulse away from the cell body.

may be myelinated or unmyelinated.

Front 6

sensory and motor neuron axons

Back 6

-myelinated schwann cells grow around the axon, and produce a fatty (lipid) myelin covering which appears white in color.

- the Na+ ions cannot flow through the myelin, so the impulse is passed from one node of ranvier to the next.
-this speeds up the rate of impulse transmission tremendously

Front 7

interneuron

Back 7

unmyelinated- no Schwann cells grow around there axons, therefore no myelin surrounding there axons.
-the Na+ ions must flow into the neuron the entire length of the axon, and this takes a lot longer.

Front 8

what is myelin?

Back 8

it helps repair damaged axons.
-if neurons are unmyelinated any damage to the neuron will be permanent if there is no myelin.

Front 9

what is axon fibres?
(terminal branches (fibres))

Back 9

they are smaller branches of the axon, that transmit nerve impulses onto the axon knobs.

Front 10

what is an axon knob?
(end plates)

Back 10

end branches (terminals) of the axon fibres. when the nerve impulses reach here it causes to axon vesicles within these structures to fuse with the edge of the cell membrane and release neurotransmitters into the synapse by exocytosis.

Front 11

what are the 5 components involved in a neural response?

Back 11

1. the receptor
2. sensory neuron
3. inter-neuron
4.motor neuron
5. effector muscle/gland.

Front 12

1. The receptors

Back 12

-(the skin) detect stimuli (change in the environment.
-changes chemical, and stimulate the sensory neuron to fire.

Front 13

2. The sensory neuron

Back 13

-receives stimuli from the receptors.
-passes the impulse onto the inter-neuron.

Front 14

3. The inter neuron

Back 14

-receives impulses from the sensory neuron

(determines response)

-passes the impulse onto the motor neuron.

Front 15

4. The motor neuron

Back 15

-receives the impulse from the inter-neurons.
-passes the impulse on to the effector

Front 16

5. The effectors (muscle/gland)

Back 16

-receives the impulse from the motor neuron.
*contracts to carry the response.

Front 17

the spinal cord and protection

Back 17

-the brain and spinal cord are surrounded by the three protective membranes called meninges.
-the bone enclosures that protect the spinal cord are called vertebrae; the skull protects the brain.

Front 18

transmission of a nerve impulse

Back 18

1. re-polarized- getting ready to fire.
2. depolarization-action potential "firing".
3. polarized- resting membrane potential.

Hint 18

1. negative in the inside of the gates, positive on the outside. K+gates open and rushes OUT by diffusion.
2. positive on the inside, negative on the outside. Na+ gates open, Na+ rushed IN by diffusion.
3. goes back to original and rests.

Front 19

what is an excitatory neuron?

Back 19

it releases neurotransmitters into the synapse that stimulate the adjacent neuron: which, if the threshold is met will cause the Na+ gates to open and the neuron to fire or depolarize.
*most neurons are excitatory

Front 20

what is an inhibitory neuron?

Back 20

it releases neurotransmitters into the synapse that prevent the adjacent neuron from firing or depolarizing by keeping the neuron in a continual state of polarization (resting potential) , which actually cause the membrane potential to be lowered, therefore making it more difficult to reach threshold.

Hint 20

ex) in serious trauma it would prevent the perception of pain. (endorphin's).

Front 21

Neural network
A and B

Back 21

Neuron A fires --> no response.
Neuron B fires --> no response.

Neuron A & B fire together --> response!

conclusion; neurons A and B are both excitatory neurons, however they could not reach the threshold on their own.

-when they are fired at the same time, together they can reach the threshold of neuron X.

Hint 21

this is called SUMMATION- the combined or added effect of 2 or more neurons firing at the same time.

Front 22

Neural network
C and D

Back 22

Neuron C fires -->
no response in x

conclusion- c is either; not able to reach the threshold on its own, or, it is an inhibitory neuron.

Neuron D fires -->
X responds fires
conclusion; D is excitatory and able to reach the threshold on its own.

Neuron C and D fires together-->
no response in X
conclusion; C is the inhibitory and it cancels out the effects of D.

Front 23

What is the Autonomic Nervous System
(ANS)

Back 23

is responsible for the INVOLUNTARY action responses throughout the body.

Hint 23

these DO NOT have conscious control.

Front 24

The sympathetic nervous system

Back 24

fires under emotional stress and causes the "fight or flight"response.

Front 25

the parasympathetic nervous system

Back 25

fires under "normal' conditions, or retures the body to normal after a "fight or flight" response.

Front 26

The autonomic nervous system

Back 26

Parasympathetic

-Your body condition is normal, bowels are digesting, blood flow is normal, everything on and working.

Hint 26

Sympathetic ("fight or flight")

-digestion, saliva glands, etc, stop. (ex) so you don't poop, if you have to fight)
-increase sweat glands (to cool body)
-heart elevates

this is cause when your nervous, angry, etc, that's why you get adrenaline rushes, because your body tries to be prepared for any situation.

Front 27

The Brain

Back 27

-is the most complex

-special feature on humans compared to other animals is that we have cerebrum's.

Front 28

Blood supply to the brain

Back 28

oxygen, nutrients (particularly glucose) are delivered to the brain by blood vessels.
-if O2 or glucose to the brain is interrupted, it disrupts the brain activity and goes into a state of unconsciousness.

Front 29

What is the central nervous system?
(CNS)

Back 29

it consists of the brain and spinal cord.

-the CNS plays a mayjor role in maintaining homeostasis.
-the brain acts as a central command post, and the spinal cord as a complex relay system.

Front 30

CNS protection

Back 30

it is protected by bone enclosure; the vertebrae and the skull.
-both brain and spinal cord are wrapped in 3 protective membranes called the MENINGES.
-cushioning the CNS is cerebrospinal fluid. it fills the spaces between the meninges and the central canal. of the spinal cord, as well as the ventricles (spaces) in the brain.

Front 31

3 mayjor divisions of the brain.

Back 31

A) Hindbrain
B) Midbrain
C) forebrain

Front 32

A) the Hindbrain

Back 32

this part of the brain mostly connects directly to the spinal cord.
-this is part of the brain that controls the basics. (breathing, heart rate, blood pressure, etc)
-is also made up of interconnected part Medulla oblongata, the cerebellum, and the pons.

Front 33

Hindbrain

MEDULLA OBLONGATA

Back 33

-the first extension of the spinal cord.
-acts like a complex relay center. (sorts in and out going info).
-nerve impulses controlling the diaphram and the muscles involved in breathing.
-it also controls heart rate and blood pressure.

Front 34

Hindbrain

CEREBELLUM

Back 34

located behind the medulla, looks like 2 large balls at the base of the brain.
-it is connected by the nerve tracts to the motor area of the cerebral cortex; it receives input from almost all of the sensory areas of the body.
-it coordinates and maintains control over all fine (small) and gross (large) motor actions including, balance and coordination.
-damage to the cerebellum affects the precision of motor activities (jerky, slurred speech, etc)

Front 35

hindbrain

PONS

Back 35

the "bridge"; it is the bulge located above the mudulla oblongata.
-its nerve fibres connect two sides of the cerebellum.
-also connects the cerebellum to the cerebrum. it also connects the forebrain (cerebrum) and the midbrain to lower brain centres including the medulla.
-it also contains parts of the breathing control system.

Front 36

B) The midbrain

Back 36

located above the pons.
-consists of 4 small bundles of grey matter which are "relay centers" for some of the reflexes, associated with the eyes and ears.

Front 37

C) The forebrain

Back 37

contains the hypothalamus, thalamus, cerebrum + cerebral cortex.

Front 38

Forebrain

THALAMUS

Back 38

located above the midbrain, the thalamus acts as a relay centre for nerve impulses going to the cerebrum.
-it affects consciousness and the preception of pain.

Front 39

Forebrain

HYPOTHALAMUS

Back 39

acts as the "control centre" for many vital functions of the autonomic nervous system (ANS)
-its role is to regulate temperature and water balance; also for hunger, thirst, and sexual drive. (FHS,LH, oxytocin)
-it controls the secretion of the anterior pituitary by secreting "releasing hormones" which travel through the connecting blood vessels; it controls the posterior pituitary through nerve impulses.

Front 40

Forebrain

CEREBRUM

Back 40

The largest part of the brain.
-it splits into 2 hemispheres by a longitudinal fissure.

Front 41

Forebrain - cerebrum

LOBES OF THE CEREBRUM

Back 41

1. frontal lobe- controls emotions, contemplation, stress, and voluntary muscle movement.
2. parietal lobe- controls perception of touch, pain, pressure, and heat on the skin.
3. temporal lobe- controls hearing (auditory), and smelling (olfactory).
4. occipital lobe- controls vision.

Front 42

what is the frontal lobes?

Back 42

controls emotions, contemplation, stress, and voluntary muscle movement.

Front 43

what is the parietal lobe?

Back 43

controls perception of touch, pain, pressure, and heat on the skin.

Front 44

what is the temporal lobe?

Back 44

controls hearing (auditory), and smelling (olfactory).

Front 45

what is the occipital lobe?

Back 45

controls vision

Front 46

what is the corpus callosum?

Back 46

it is the nerve tract that connects the 2 hemispheres of the brain together.

Front 47

cerebral cortexes

Back 47

divided into 3 cortexes;
1. motor cortex
2. sensory cortex
3. associative cortex

Front 48

what is (1.) the motor cortex?

Back 48

located at the top of the frontal lobe, controls VOLUNTARY muscle movement.

Front 49

what is (2.) the sensory cortex?

Back 49

located behind the motor cortex in the parietal lobe, receives sensory impulses from the body.

Front 50

what is (3.) the associative cortex?

Back 50

covers the rest of the cerebrum; it is the site of planning, contemplation, conceptualization, and also associated with recall and memory.