Lecture 4 muscle + nerves

Question 1

Muscle tissue structure/function

Answer 1

Elongated muscle cells (myocytes) hydrolyse Adenosine Triphosphate (ATP) to generate force. Movements, posture, generates heat

Question 2

3 types of muscle tissue

Answer 2

Skeletal, cardiac, smooth

Question 3

Skeletal muscle structure

Answer 3

650 of them; striated, usually voluntary and attached to bones by tendons, cylindrical fibres, multi-nuclei

Question 4

Skeletal muscle function

Answer 4

generates heat, produces body movement, and maintains posture from contractions

Question 5

sarcomere

Answer 5

basic unit of myofibrils, defined by z discs on each side

Question 6

myofibril structure

Answer 6

consists of sarcomere units made of thick (myosin) and thin (actin) myofilaments, surrounded in endomysium

Question 7

fascicles

Answer 7

bundles of myofibrils covered in perimysium

Question 8

epimysium

Answer 8

surrounds muscle

Question 9

sarcoplasm and sarcolemma

Answer 9

muscle cell cytoplasm and muscle cell membrane

Question 10

muscle fibre cell structure

Answer 10

Covered in endomysium, then double layered sarcolemma membrane. Sarcoplasm contains myofilaments actin and myosin.

Question 11

IZ

Answer 11

Z discs (made from actinins which bind actin between sarcomeres) pass thru I band (only thin)

Question 12

MAH

Answer 12

M line passes thru A (H bands (only thick) + overlap areas) and holds thick myosin together

Question 13

Titin

Answer 13

Links Z disc to M line like spring providing tension in I band

Question 14

Cardiac muscle

Answer 14

Striated, branched, ends of fibres join end - end thru intercalated discs, single nuclei, involuntary

Question 15

Intercalated discs

Answer 15

Desmosomes for adhesion, gap junctions for communication/coordination/rapid conduction

Question 16

Purkinje fibres

Answer 16

Specialised heart cells that conduct electrical activity; less myofibrils, more connexins

Question 17

Smooth muscle structure

Answer 17

non striated but still have myosin/actin, single central nuclei, involuntary, dense bodies major protein is actinin, also connected by non-contractile intermediate filaments

Question 18

PNS afferent and efferent functions

Answer 18

Sensory info to CNS, motor info to organs

Question 19

Nervous system functions

Answer 19

Sensory, Motor, Integrative

Question 20

Sensory

Answer 20

Detects internal + external stimuli for homeostasis

Question 21

Motor

Answer 21

stimulation of effectors (muscles and glands) and initiates voluntary movement

Question 22

Integrative

Answer 22

Analyse and store info for perception, behaviour, memory

Question 23

2 nervous tissue cell types

Answer 23

Neuron (large), Neuroglia (supportive, small)

Question 24

Neuron cell structure

Answer 24

Nucleus in cell body, dendrites receive nerve impulses (action potentials), axon sends out nerve impulses

Question 25

4 neuron types

Answer 25

Multi-polar, bipolar, unipolar, anaxonic

Question 26

Multi polar neurons

Answer 26

two or more dendrites + one axon, most common type.

Question 27

Bipolar neurons

Answer 27

one dendrite + one axon, rare and small

Question 28

Unipolar neurons

Answer 28

continuous dentrite and axon with cell body off to side

Question 29

Anaxonic neurons

Answer 29

Very rare, dunno function, dendrites and axons indistinguishable, found in brain and special sense organs

Question 30

All Motor neurons are what type

Answer 30

Multipolar

Question 31

Special senses (sight, smell, hearing) what neuron type

Answer 31

Bipolar

Question 32

CNS neuroglia

Answer 32

Astrocytes, oligodendrocytes, microglia, ependymal cells

Question 33

PNS neuroglia

Answer 33

Satellite cells, Schwann cells

Question 34

Astrocytes function

Answer 34

Support and repair, maintain environment around neutron via regulating ions, maintains BBB by influencing blood vessel permeability

Question 35

Astrocytes features

Answer 35

Star shaped, largest and most numerous of neuroglia; forms Syncytium network.

Question 36

Oligodendrocytes function

Answer 36

Forms insulating myelin sheaths (protein lipid layer) around CNS axons to accelerate action potential

Question 37

Oligodendrocyte vs Schwann cells

Answer 37

One Oligo cell can myelinate more than one axon per cell, one Schwann cell can only myelinate one axon per cell(but can support/tube more than one axon)

Question 38

Microglia

Answer 38

Resident macrophages (phagocytic) for protection of CNS

Question 39

Ependymal cells function

Answer 39

Produce CerebroSpinal Fluid (CSF), lines central canal of spinal chord and other CSF filled ventricles (in brain), CSF mechanical buffer and moves nutrients/waste

Question 40

Ependymal cell structure

Answer 40

Predominantly simple cuboidal, have BOTH microvilli and cilia

Question 41

Schwann cell function

Answer 41

Forms insulating myelin sheath around PNS axons or just support/surround non-myelinated axons

Question 42

Satellite cells function

Answer 42

Surround neuron cell bodies to provide support and fluid exchange
(equiv to astrocytes of cns)

Question 43

Neuroglia features

Answer 43

Don’t communicate with action potentials (use chemicals), smaller than neurons but more numerous, in CNS and PNS, can divide within mature nervous system

Question 44

Neuroglia functions

Answer 44

Physical structure and repair framework of nervous tissue, phagocytosis, nutrient supply, regulate interstitial fluid in neural tissue

Question 45

Smallest/longest skeletal muscle

Answer 45

Smallest: Stapedius -1.25mm- to prevent hyperacusis (loud sound deafening)
Largest: Sartorius -up to 60cm- twist leg to look at bottom of feet

Question 46

Smooth muscle locations

Answer 46

Blood vessels; iris of eye; digestive, urinary, reproductive systems, intestines, skin erector pili

Question 47

what do astrocytes communicate with

Answer 47

gliotransmitters (e.g. glutamate)

Question 48

Ependymal mechanical buffer function

Answer 48

Absorbs shock by acting as cushioning