Lecture 4: Muscle and Nervous tissue

Question 1

Definition of Muscle tissue and what system is it part of

Answer 1

elongated cells that use energy from hydrolysis of ATP to generate force. It is part of the Muscular system.

Question 2

Muscle cells also called

Answer 2

myocyte, muscle fibre

Question 3

What is the main purposes of Muscular tissue

Answer 3

To produce body movements, maintain posture, generate heat and provide protection.

Question 4

3 types of Muscle tissue

Answer 4

Skeletal, cardiac, smooth

Question 5

Skeletal muscle : basic structure, function and location

Answer 5

Structure: striated, multinucleated cells that are long. They are found attached to bones by tendons (CT) and functions are motion, heat, posture and protection.

Question 6

Out of the three types of skeletal muscle which is under voluntary control.

Answer 6

Skeletal muscle. Cardiac and smooth muscle is under involuntary control.

Question 7

Smallest skeletal muscle is the: … It is found in the: …. and is responsible for…

Answer 7

Stapedius, ear, stabilizes the stapes, prevents hyperacusis

Question 8

Longest skeletal muscle is the: … It is found in the: …. and is responsible for…

Answer 8

Sartorius, hip , rotating the foot

Question 9

List the layers of structure from biggest to smallest in what actually makes the skeletal muscle tissue. (> = made of)

Answer 9

Skeletal muscle tissue > bundles of muscle fibres called fascicles. One muscle fibre> myofibrils within the sarcoplasm> myofilaments

Question 10

Tendon: what type of CT and where is it found

Answer 10

Dense regular CT. found attaching muscle to bone.

Question 11

myofibrils are made of two types of myofilaments

Answer 11

Thin filaments - actin and thick filaments - myosin

Question 12

In the microscopic anatomy of muscle fibre, which component fills the sarcoplasm of the muscle fibre and which component is arranged in compartments called sarcomeres

Answer 12

Myofibrils fill the sarcoplasm. Myofilaments are arranged in sarcomeres.

Question 13

Epimysium: what type of CT and where is it found

Answer 13

Dense irregular CT. surrounds anatomical muscle at the biggest level.

Question 14

Perimysium : what type of CT and where is it found

Answer 14

Dense irregular CT. surrounds the fascicles (bundles of muscle fibres)

Question 15

Endomysium : what type of CT and where is it found

Answer 15

Areolar CT. surrounds each muscle fibres (in between cells)- the layer where the capillaries and nerves are passing through

Question 16

What is the Sarcolemma

Answer 16

cell membrane of the muscle cell/ muscle fibre.

Question 17

Which sections of the myofibril look smaller when the muscle contracts

Answer 17

the H zone, and the I band. The dark bands of the muscle look bigger (A band)

Question 18

A band: dark What is it and where is it

Answer 18

The middle 3/4 of the sarcomere that has all thick filaments. It also includes any overlapping thin filaments that happen to be there and the H zone.

Question 19

I band : What is it and where is it

Answer 19

The last 1/8 of the sarcomere and a 1/8 section after the Z disc where there are only thin filaments

Question 20

H zone : What is it and where is it

Answer 20

It is a zone around the M line where there are are only thick filaments in the middle. (no thin filaments)

Question 21

M line: What is it and where is it

Answer 21

a disc that holds the thick filaments together in the Middle of the sarcomere

Question 22

Z disc/line : Where is it and what is it.

Answer 22

It is a dense plate of material that passes through the centre of the I band separating sarcomeres. It is made of actinins that link the filaments of adjacent sarcomeres

Question 23

Cardiac muscle : basic structure, function and location

Answer 23

Striated, branched cells with single central nucleus. Fibres join end to end by intercalated discs. Found in the heart wall and used to pump blood.

Question 24

Intercalated discs contain what two things. What do those two things do?

Answer 24

Desmosomes that bind intermediate filaments to give adhesion during contraction.
Gap junctions for rapid conduction of contraction stimulus.

Question 25

What is the one muscle cell that is not striated

Answer 25

smooth muscle; cardiac and skeletal is striated.

Question 26

What are Purkinje fibres

Answer 26

specialised muscle cells that conduct electrical signals around the heart so have less myofibrils and special connexins.

Question 27

Smooth muscle: deep structure

Answer 27

Spindle shaped cells with intermediate filaments strapping diamonds across the surface, the corners are dense bodies, with thin filaments connecting vertically down the diamond with a band of thick filaments in middle of these thin filaments.

Question 28

Smooth muscle : basic structure, function and location

Answer 28

Non striated, spindle cells with a single central nucleus. Function is in constriction and propulsion. Its found in the walls of hollow internal structures- eg blood vessels. intestines, skin, iris.

Question 29

What muscle cells have centrally located nucleus

Answer 29

only smooth and cardiac muscle . skeletal muscle has peripheral multinucleated cells.

Question 30

Where does the smooth muscle cell have lots of gap junctions and no gap junctions

Answer 30

Lots: gut. No gap junctions: Iris

Question 31

Describe the mechanism of contraction in a smooth muscle cell

Answer 31

During contraction, tension is transmitted to the intermediate filaments and the cell twists as it contracts about these "stable rods."

Question 32

Nervous tissue is part of the Nervous system. What are the two subdivisions of the nervous system

Answer 32

Central Nervous System which includes the Brain, spinal cord and optic nerve. Peripheral Nervous System which includes all other nervous tissue

Question 33

What are the two categories of Nervous tissue

Answer 33

neurons ( longest cells) , neuroglia (short supportive cells)

Question 34

Multipolar neurons : structure and functional classification

Answer 34

2 or more dendrites and a single axon. Convey action potential from CNS to an effector (muscle or gland) as a motor neuron or be a interneuron between sensory and motor neurons.

Question 35

Bipolar neurons - structure and functional classification

Answer 35

Has cell body between one distinct dendrite and one axon. Rare, Found in special sense organs relaying information from receptor to neurons.

Question 36

Unipolar Neuron -structure and functional classification

Answer 36

continuous dendrite to axon (part after dendrites converge) process with cell body off to the side. Sensory neuron that conveys action potential from a receptor into the CNS.

Question 37

Anaxonic neuron- brain

Answer 37

Can't tell dendrites from axons, found in brain and special sense organs but functions not well understood.

Question 38

Neuroglia function

Answer 38

physical structure of nervous tissue, repair framework, phagocytosis, nutrient supply to neurons, regulate environment

Question 39

What is the network of astrocytes

Answer 39

Syncytium

Question 40

Astrocytes : 4 functions

Answer 40

1. Maintain the blood brain barrier by wrapping around bV. 2. Have microfilaments that support neurons and repair neurons (scar) 3. Maintain the chemical environment 4. Communicate with neurons via gliotransmitters.

Question 41

Oligodendrocytes (few tree cells) function

Answer 41

Form insulating multilayered myelin sheath around CNS axons. Can myelinate more than one neuron, accelerate the action potential.

Question 42

Microglia function

Answer 42

Resident macrophage that eats microbes and damaged tissue. It can be inactive and active.

Question 43

Ependymal cells found

Answer 43

Lining the Cerebrospinal fluid filled ventricles of the brain and central canal of spinal cord

Question 44

Ependymal cells function

Answer 44

producing cerebrospinal fluid protects the brain as a mechanical buffer. They also assist circulation of CSF which moves nutrients and wastes.

Question 45

Ependymal cell structure

Answer 45

single layer of cuboidal cells that have cillia for flow and microvilli for sampling

Question 46

Schwann cells function: myelinating and non myelinating

Answer 46

1 schwann cell per axon can form insulating myelin sheath for PNS neuron for M. For nM it can just support several non myelinated axons

Question 47

Are actin and myosin filaments found in all muscle cell types

Answer 47

yes

Question 48

What are dense bodies

Answer 48

Made of protein actinin, and functionally similar to z discs.

Question 49

What are the three things that nervous system helps us to do

Answer 49

maintain homoestasis, voluntary movements, perception, behaviour and memory.

Question 50

What are the main structural features of neurons

Answer 50

has a Cell body (soma) into which short branched dendrites convey action potentials and from which a longer single axon conducts nerve impulses to another neuron or tissue.

Question 51

What is the metabolic and mitotic rate of neurons

Answer 51

High metabolic rate (die rapidly w/out O2) and do not divide.

Question 52

What are the 4 types of neurons

Answer 52

Multipolar, bipolar, unipolar and anaxonic

Question 53

What are the types of neuroglia in the PNS

Answer 53

Myelinating and non myelinating Schwann cells, Satellite

Question 54

What are the types of neuroglia in the CNS

Answer 54

Astrocytes, ogliodendrocytes, ependymal, microglia

Question 55

What is the difference between afferent and efferent

Answer 55

afferent is directed in (of CNS) and efferent is directed out (of CNS)

Question 56

Satellite cells function

Answer 56

Provide structural support around cell bodies of PNS neurons. regulates fluid exchange between cell bodies and interstitial fluid.

Question 57

What are the sensory, integrative and motor functions of the nervous system

Answer 57

1. detection of internal/external stimuli and transfer to CNS 2. Analysis and storing of information 3. Stimulation of effectors.