BIO MED TERM 2 NERVE CELL + BRAIN

Question 1

Nuron =
Neuroglia =

Answer 1

Nuron = Nerve cell
Neuroglia = Supporting nerve cell

Question 2

Skeletal muscle characteristics :

Answer 2

Excitability and Irritability - able to be stimulated
Contractions
Extensibility - shorter or longer
Elasticity - ability to come back to original length and shape

Question 3

NEUROGLIA OR GLIAL CELLS

Answer 3

They protect the neurons and aid their function
They bind neurons together and provide a supportive
framework for the nervous tissue
They function as an insulation
Controls the chemical environment of the nervous tissue

Question 4

Epimysium

Answer 4

Dense connective tissue covering the entire muscle
Each muscle is made of bundles of fascicles, parallel to each
other

Question 5

Perimysium

Answer 5

Fibrous connective tissue covering each fascicle
Each fascicle is made up of bundles of muscle cells (muscle
fibres), parallel to each other.

Question 6

Endomysium

Answer 6

Fine sheath of connective tissue covering each muscle
cell

Question 7

Sarcolemma

Answer 7

Cell membrane of muscle cell.
Each muscle cell can have one or more nucleus.
just beneath the sarcolemma.

Question 8

Sarcoplasm

Answer 8

Cytoplasm of muscle cell
It is rich in mitochondria and glycogen.
Myoglobin - unique oxygen binding protein that
stores oxygen within the sarcoplasm.

Question 9

Myofibrils

Answer 9

Myofibrils
Each muscle cell is made up of myofibrils

Question 10

Muscle filaments
Muscle proteins

Answer 10

Each myofibril is made up of muscle filaments
They alternate to form the dark and light bands

Each muscle filament is made up of muscle protein
Myosin or Actin

Question 11

what is above and under the Sacrolemma?

Answer 11

the Sacrolemma is under the Endomysium of the muscle fibre and inside the Sacrolemma are microfibril, inside microfibril are 2 protiens of MYOSIN AND ACTIN

Question 12

A segment of myofibril is :

Answer 12

Sacromere - each has actin and myosin

Question 13

Aponeurosis

Answer 13

sheet like coverings attaches
two muscles.

Question 14

Afferent nerves

Answer 14

Sensory :
Carry impulses towards the CNS from receptors all over the body

Question 15

Efferent

Answer 15

Motor :
Carry impulses AWAY rom the CNS to the effector organs (muscles and glands)

Question 16

CNS

Answer 16

Brain and Spinal cord

– occupy dorsal body cavity
– Integrating and
communicating centre

– Interprets incoming sensory information and dictates motor
responses based on past experience, reflexes and current
conditions

Question 17

Peripheral Nervous System (PNS)

Answer 17

Outside the CNS; Consists of nerves that extend from the brain and
spinal cord.

Cranial nerves :
carry impulses to and from the brain
ii.
Spinal nerves:
carry impulses to and from the spinal cord
– Serves as communicating lines that link all parts of the body to
the CNS

Question 18

Peripheral Nervous System consits of two types

Answer 18

Somatic nervous system – impulses from and to voluntary
muscles

a. Sensory (afferent) nerves
* Carry impulses from the skin, voluntary skeletal muscles and
joints to the brain.

b. Motor (afferent) nerves
* Carries impulses from the CNS to the voluntary skeletal muscles.

Autonomic nervous system – impulses from and to involuntary
muscles

a. Sympathetic
a. Increasing (arousing) effect on activity.

b. Parasympathetic
a. Decreasing (calming) effect on activity.

Question 19

Nerves form cord like structures which can have 2 forms

Answer 19

1. Bundles of axons that travel together in the PNS
   * Covered by connective tissue (epi, peri and
   endoneurium)
   * Peripheral nerves
2. Bundle of axons that travel together in the CNS
   * Have no connective tissue covering
   * Tracts

Question 20

Neuron (Nerve cell)
Composed of:

fun fact:

Answer 20

1. Cell body
2. Axon
3. Dendrites

Permanent cells (do not under go mitosis) and they have a
high metabolic rate.

Question 21

5 Main structures of a Nuron

Answer 21

Mitochondrion
Dendrite
Myelin sheath
Schwann cell
Axon terminal

• Contains the nucleus and nucleolus
• Has no centrioles (amitotic)
• Has an axon hillock
• Cone shaped area where the axon arises

Question 22

NERVE CELL BODY (SOMA)

Answer 22

• Contains the nucleus and nucleolus
• Has no centrioles (amitotic)
• Has an axon hillock
• Cone shaped area where the axon arises

Question 23

Dendrites

Answer 23

Short, tapering and branched processes
ii. They are the receiving or input regions of the neuron
iii. They convey incoming messages to the cell body / soma

Question 24

Axons

Answer 24

i. They are slender processes arising from the axon hillock
ii. There is only one axon per neuron.
iii. The ends of the axon forms branched terminals with knob-like
structures – axon terminals.
iv. Chemical substances called neurotransmitters are stored in
vesicles in the axon terminals

Question 25

Myelin Sheath

Answer 25

• White, segmented sheath around most long axons
• Composed of phospholipids
• Formed by supporting cells / neuroglial cells:
• Schwann cells in the PNS
• Oligodendrocytes in the CNS
• Myelin sheath is formed by the Schwann cells wrapping around the
  axon.
• Adjacent Schwann cells do not touch each other and the gap is called
  node of Ranvier.

Question 26

Functions of myelin sheath:

Answer 26

Protect the axon.
ii. Electrically insulate the nerve fibres from one another.
iii. Increases the speed of transmission of nerve impulse.

Question 27

Properties of the neuron

Answer 27

1. Irritability – highly excitable tissue
   * Capable of generating a nerve impulse (action
   potential) when irritated or stimulated e.g. touch to the
   skin
2. Conductivity – transmit impulse along the entire length of
   the nerve fibre
   * Allows communication with other neurons, muscles
   and glands.

Question 28

Anaxonic neuron

Answer 28

Nerves found only in the CNS

Question 29

Meninges –

Answer 29

s – membranes covering the brain
* Dura mater – outermost tough fibrous covering
* Arachnoid mater – middle vascular covering
* Pia mater – inner most delicate membranous covering

Question 30

Arachnoid Mater

Answer 30

Middle layer with web-like extensions

• Separated from the dura mater by the subdural space
• Subarachnoid space – between the arachnoid mater and
  the pia mater, contains cerebrospinal fluid and blood
  vessels.
• Arachnoid villi protrude into the superior sagittal sinus and
  permit CSF reabsorption.

Question 31

• Arachnoid villi

Answer 31

• Arachnoid villi protrude into the superior sagittal sinus and
  permit CSF reabsorption.

Question 32

• Subarachnoid space –

Answer 32

• Subarachnoid space – between the arachnoid mater and
  the pia mater, contains cerebrospinal fluid and blood
  vessels.

Question 33

Pia Mater

Answer 33

• Layer of delicate vascularized connective tissue that clings tightly to
  the brain.

Question 34

Dura Mater

Answer 34

Strongest meninges
* Consists of:
* Two layers of fibrous connective tissue (around the
brain)
* Separates to form dural sinuses
* Dural septa limit excessive movement of the brain
* Falx cerebri—in the longitudinal fissure; attached to
crista galli.
* Falx cerebelli—along the vermis of the cerebellum. * Tentorium cerebelli—horizontal dural fold over
cerebellum and in the transverse fissure

Question 35

Cerebrospinal Fluid (CSF)

Answer 35

Fluid present within the cavities of the brain or spinal cord and in the
subarachnoid space.
* Secreted by the choroid plexus (network of blood vessels) in the
cavity of the brain.
* Drained into the large thin-walled veins, dural sinuses in the
duramater.

Question 36

Function of CSF

Answer 36

function:
* Floats (buoyancy) the brain so it does not get crushed under its own
weight.
* Cushions the CNS from blows and trauma to the head.
* Helps nourish the nervous tissue.
* Carries chemical signals.