Muscle and Nerve tissue

Question 1

Features and functions of skeletal muscle

Answer 1

Cylindrical fibres
Under conscious control (not voluntary)
Heat, posture, protection

Question 2

Structure of muscle fibres

Answer 2

Multinucleated
Long fibres
Striated

Question 3

Size and structure of myofibrils

Answer 3

2um diametre
Extend length of muscle fibre
arrangement forms striations

Question 4

Size of components of myofibrils

Answer 4

Actin - 8nm diametre, 1.5 um length

Myosin - 16nm diametre, 1.5 um length

Question 5

The 3 connective tissues of skeletal muscle

Answer 5

Epimysium - Surrounds muscles
Perimysium - Surrounds fascicles
Endomysium - Surrounds individual muscle fibres

Question 6

Bands and lines of muscle fibres

Answer 6

A line - Actin and Myosin
I line - Actin only
H line - Myosin only
M line - centre of sarcomere
Z line - between sarcomeres, actinins hold sarcomeres together

Question 7

Structure of cardiac muscle

Answer 7

Striated
Branched
Single nucleus
Joined by intercalated discs
Purkinje fibres (fewer myofibrils, more gap junctions)

Question 8

Components of intercalated discs

Answer 8

Desmosomes

Gap junctions

Question 9

Location of smooth muscle

Answer 9

Walls of hollow internal structures

e.g intestines, blood vessel walls

Question 10

Features of smooth muscle

Answer 10

Small, short and spindle shaped
Single central nucleus
Non striated

Question 11

Structure of smooth muscle

Answer 11

Bundles of myosin and actin still present
Both thin and intermediate filaments attach to dense bodies (consisting largely of actinin)
Intermediate filaments do not contract - the cell ‘twists’ around these stable rods

Question 12

Function of nervous system

Answer 12

Maintain homeostasis (along with the endocrine system)
Initiates voluntary movements
Responsible for perception, behaviour and memory

Question 13

3 major functions of nervous system

Answer 13

Sensory
Integrative
Motor

Question 14

Two cell types of nervous tissue

Answer 14

Nerve cells

Supporting neuroglia

Question 15

Structures of neurons

Answer 15

Dendrites - receive other impulses
Axon - output portion of neuron
Trigger zone
Myelin sheathe
Axon terminal
Cell body

Question 16

Features of neurons

Answer 16

High metabolic rate (die quickly without O2)

Do not divide

Question 17

Types of neurons

Answer 17

Multipolar
Bipolar
Unipolar
Anaxonic

Question 18

Features of multipolar neurons

Answer 18

Many dendrites
Most common
Make up all motor neurons

Question 19

Features of bipolar neurons

Answer 19

1 dendrite and 1 axon with cell body between
Rare and small (30 um)
Often in special sense organs

Question 20

Features of unipolar neurons

Answer 20

Dendrites connected to axon
Cell body on side
Most sensory nerves
Very long

Question 21

Feature of anaxonic neuron

Answer 21

Dendrites and axon indistinguishable
Rare and poorly understood
Found in brain and special sense organs

Question 22

Features of neuroglia

Answer 22

Found in CNS and PNS
50% volume of CNS (acts as glue)
5-50x more numerous than neurons
Small
Do not propagate AP
Divide

Question 23

Function of neuroglia

Answer 23

Give structure to nervous tissue
Repair nervous tissue
Phagocytosis
Nutrient supply
Regulate interstitial fluid

Question 24

List CNS neuroglia

Answer 24

Astrocytes
Oligodendrocytes
Microglia
Ependymal cells

Question 25

Function and features of astrocytes

Answer 25

Star shaped - most abundant neuroglia
Support and repair
Communicate with neuronsvia gliotransmitters
Regulate environment
Maintain blood brain barrier

Question 26

Function of oligodendrocytes

Answer 26

Form insulating multilayered myelin sheathe around axon in CNS
Can myelinate more than one axon

Question 27

Function of microglia

Answer 27

Phagocytosis

Question 28

Function of ependymal cells

Answer 28

Produce cerebrospinal fluid (CSF)
Line ventricles of brain and central canal of spianl cord
Predominantly cuboidal cells - have cilia for flow and microvili for sampling
CSF moves nutrients and waste

Question 29

Peripheral system neuroglia

Answer 29

Schwann cells - can myelinate one axon but can support many

Satellite cells - surround cell bodies. Support and fluid exchange