nervous

Question 1

what’s in the PNS?

Answer 1

The portion of nervous system outside CNS
consists mainly of nerves that extend from brain and spinal cord
1) Spinal nerves to and from spinal cord
2) Cranial nerves to and from brain

cranial nerves, spinal nerves, ganglia

Question 2

what is motor output?

Answer 2

is the conduction of signals from integration centers to effector cells.
- Effector cells carry out the body’s response to a stimulus

Question 3

what center is open for integration?

Answer 3

CNS

Question 4

how are impulses conducted along a nerve?

Answer 4

Dendrite  cell body  axon hillock  axon

Question 5

what does the myelin sheath cover?

Answer 5

axon

Question 6

where are the neurotransmitters stored?

Answer 6

Axon endings are called synaptic terminals: they contain neurotransmitters which conduct a signal across a synapse

Question 7

whats a reflex arc?

Answer 7

The reflex arc is a simple nerve circuit. A reflex is an autonomic response.

Question 8

whats the knee reflex called?

Answer 8

patellar

Question 9

what does a reflex check?

Answer 9

A reflex checks the health of the nervous tissue between the periphery and the spinal cord

Question 10

what are roots?

Answer 10

There are bundles of axons, called roots which connect the spinal nerves to the spinal cord

Question 11

what are the two types of roots?

Answer 11

The posterior ones (dorsal) are groups of sensory axons, which conduct nerve impulses from peripheral sensory receptors (such as those in the skin) to the CNS.

The anterior ones (ventral) are groups of motor neurons, which carry mesages from the CNS to the effectors, which could be muscles or glands.

Question 12

whats a ganglion?

Answer 12

A ganglion is a cluster of nerve cell bodies within the PNS

Question 13

whats a nucleus?

Answer 13

A nucleus is a cluster of nerve cell bodies within the CNS.

Question 14

what are meninges and what are the different layers?

Answer 14

Meninges: are layers of connective tissues which cover the brain and spinal cord.

Moving from outside towards the brain or spinal cord these layers are
1) the dura mater
2) the arachnoid mater
3) the pia mater

Question 15

how do dorsal and ventral roots link?

Answer 15

As the spinal nerve nears the spinal cord, it splits into dorsal and ventral roots. The dorsal root contains only the axons of sensory neurons, whereas the ventral roots contain only the axons of the motor neurons.

Question 16

what are the different glia supporting cells and where are they found?

Answer 16

Astrocytes are found within the CNS. They provide structural and metabolic support
2. Oligodendrocytes are found within the CNS.
Form a myelin sheath by insulating axons.
3. Schwann cells are found within the PNS.
Form a myelin sheath by insulating axons.

4. Ependymal cells: Cilia beat to circulate CSF

Question 17

what do astrocytes do?

Answer 17

By inducing the formation of tight junctions between capillary cells astrocytes help form the blood-brain barrier.
Like neurons, astrocytes communicate with one another via chemical signals.

Question 18

wat do oligodendrocytes and Schwann cells do?

Answer 18

Form a myelin sheath by insulating axons.

Question 19

what do ependymal cells do?

Answer 19

Cilia beat to circulate CSF
- Line the central cavities of the brain and spinal column
- Form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS cells

Question 20

where are anions and cations more concentrated?

Answer 20

Anions are more concentrated within a cell.
Cations are more concentrated in the extracellular fluid

Question 21

what are the two types of gated ion channels?

Answer 21

chemically gated and voltage gated

Question 22

what are the cations?

Answer 22

K+ the principal intracellular cation.
Na+ is the principal extracellular cation.

Question 23

what are the anions?

Answer 23

Proteins, amino acids, sulfate, and phosphate are the principal intracellular anions.
Cl– is principal extracellular anion.

Question 24

what do ungated channels do?

Answer 24

allow ions to diffuse across the plasma membrane.
These channels are always open.
This diffusion does not achieve an equilibrium since sodium-potassium pump transports these ions against their concentration gradients.

Question 25

what are the types of gated ion channels?

Answer 25

1) Chemically-gated ion channels open or close in response to a chemical stimulus (ex neurotransmitter)
2) Voltage-gated ion channels open or close in response to a change in membrane potential.
Hyperpolarization: Gated K+ channels open so K+ diffuses out of the cell and so the membrane potential becomes more negative.
Depolarization: Gated Na+ channels open so Na+ diffuses into the cell and the membrane potential becomes less negative.

3) Mechanically gated channels: Open and close in response to physical deformation of receptors, as in sensory receptors
 

Question 26

true or false, the Na K pump works to create a gradient, to then allow the gated channels to open and make action potentials

Answer 26

true

Question 27

what are the two gates of the voltage gated Na+ Chanel?

Answer 27

1. Closed activation gates open rapidly in response to depolarization. The opening of the activation gates allows sodium ions INTO the cell leading to a greater depolarization.
2. Open inactivation gates close slowly in response to threshold depolarization. This prevents any further sodium ions from entering the cell.

Question 28

what happens during the undershoot?

Answer 28

During the undershoot both the Na+ channel’s activation and inactivation gates are closed.

Question 29

what is saltatory conduction?

Answer 29

In myelinated neurons only unmyelinated regions of the axon depolarize. The action potential jumps from one node of Ranvier to the next. This is called saltatory conduction

node of ranvier is depolarized region

Question 30

describe both type of synapses?

Answer 30

Electrical Synapses.
Action potentials travels directly from the presynaptic to the postsynaptic cells via gap junctions.
Chemical Synapses.
More common than electrical synapses.
Postsynaptic chemically-gated channels exist for ions such as Na+, K+, and Cl-.
Depending on which gates open the postsynaptic neuron can depolarize or hyperpolarize.

Question 31

how does a neurotransmitter get released?

Answer 31

An action potential arrives at the pre-synaptic membrane and causes the neurotransmitter containing vesicles to fuse with the pre-synaptic membrane. The neurotransmitter will be released into the synaptic cleft, will bind to the ion channel on the post-synaptic membrane and cause changes in the ion channels of the post-synaptic membrane
 

Question 32

what’s the enteric nervous system?

Answer 32

the digestive system is endowed with its own, local nervous system referred to as the enteric or intrinsic nervous system. The magnitude and complexity of the enteric nervous system is immense - it contains as many neurons as the spinal cord.

Question 33

what are the three brain regions?

Answer 33

forebrain: hypothalamus, cerebrum
midbrain
hindbrain (pons and medulla)