Nervous system

Question 1

What are the organs of the nervous system

Answer 1

Brain, spinal cord, peripheral nerves, sense organs

Question 2

What are the 2 divisions of the nervous system

Answer 2

CNS: brain and spinal cord
PNS: nerves and sense organs

Question 3

What are 3 functions of the CNS

Answer 3

To process and coordinate:

Sensory data (input):
from inside and outside the body

Motor commands (output):
to control activities of peripheral organs (e.g., skeletal muscles)

Higher functions of the brain:
intelligence, memory, learning, emotion

Question 4

What are 3 functions of the PNS

Answer 4

Connect the nervous system with other systems

Deliver sensory information to the CNS (from the sensory organs)

Carry motor commands to peripheral tissues and effectors (muscles, glands etc)

Question 5

What 2 types of cells make up neural tissue

Answer 5

Neurones and Neuroglia (glial cells)

Question 6

What two types of matter make up neural tissue

Answer 6

Grey matter: mainly cell bodies and unmyelinated neurones

White matter: mainly axons of myelinated neurones

Question 7

Describe the structure of a neurone

Answer 7

Cell body containing a nucleus and perikaryon

Dendrites coming off cell body

Schwann cells form myelin sheath around the axon

Gaps between internode are nodes of ranvier

Question 8

Describe the structure of a synapse

Answer 8

Axon
synaptic vesicles
Synapse - gap
Neurotransmitter
Receptor
Dendrites

Question 9

What is an anaxonic neuron

Answer 9

Anaxonic neurons have more than two processes- all dendrites.
brain and special sense organs

Question 10

What are bipolar neurones

Answer 10

Bipolar neurons have two processes separated by the
cell body.
rare – special sense organs

Question 11

What are unipolar neurones

Answer 11

Unipolar neurons have a single elongated process, with the cell body located off to the side.
common sensory type

Question 12

What are multipolar neurones

Answer 12

Multipolar neurons have more than two processes; there is a single axon and multiple dendrites.
somatic motor and autonomic nerves

Question 13

What is the direction of impulse for sensory neurones

Answer 13

from receptors to CNS
from lower to higher CNS levels

Question 14

What is the direction of impulse for association (inter) neurones

Answer 14

from sensory to motor neurones

Question 15

What is the direction of impulse for motor neurones

Answer 15

from CNS to muscles
from higher to lower CNS levels

Question 16

Efferent autonomic nerve pathways

Answer 16

have a 2-neurone arrangement comprising a pre- and a post-ganglionic nerve

Question 17

Efferent somatic pathways

Answer 17

have a single neurone from CNS to effector

Question 18

Types of neuroglia in the CNS

Answer 18

Ependymal cells
Astrocytes
Oligodendrocytes
Microglia

Question 19

Types of neurolgia in the PNS

Answer 19

Schwann Cells
Satellite Cells

Question 20

What is the resting membrane potential of a nerve cell

Answer 20

-70mV

Question 21

Why is there are resting membrane potential

Answer 21

Due to the uneven distribution of charged particles on either side of the cell membrane and selective membrane permeability to ions

Question 22

Why does the resting membrane potential develop

Answer 22

Organic Anions
Na+/K+ pump
Uneven stoichiometry
Electrogenic
Membrane permeability
More permeable to K+ than to Na+
Ionic Gradients and Equilibrium potentials
ionic concentration in IntraCF and ExtraCF and electrical charge

Question 23

Where is resting membrane potential

Answer 23

Periphery of the cell

Question 24

What two types of force influence the movement of ions across the plasma membrane

Answer 24

Chemical gradients and electrical gradients

Question 25

What is the chemical gradient

Answer 25

Ions want to pass from areas of high concentration to low concentration

Na+ wants to pass into the cell

K+ wants to pass out the cell

Question 26

What is the electrical gradient

Answer 26

Ions want to pass to areas of opposite charge

Both Na+ and K+ want to pass into the cell

Question 27

What is the electrochemical gradient

Answer 27

the balance of forces acting upon an ionic species

Na+ both electrical and chemical gradients attract Na+ into the cell

K+ the chemical (out) and electrical (in) oppose one another

Question 28

What is the equilibrium potential of an ion

Answer 28

The voltage that is achieved when the plasma membrane is exclusively permeable to that ion

Question 29

When does equilibrium potential occur

Answer 29

When the chemical gradient force is equal and opposite to the electrical gradient force

Question 30

What is the equation at body temp for equilibrium potential

Answer 30

Ex= 61/n x log ([X]0/[X]i)

61 = constant derived from temp

n = valency of the ion X

log… = ionic concentration gradient across the membrane