Topic 4: The Muscular System

Front 1

What are the two overall classifications of muscles in the human body?

Back 1

1. Striated

2. Non-striated

Front 2

Striated muscles

Back 2

Pattern of muscle cell proteins overlapping; appearing as dark lines perpendicular to the way the myofiber (muscle cell) is running.

Gives the appearance of stripes.

Front 3

What are two examples of striated muscles?

Back 3

Cardiac and skeletal muscle.

Front 4

What are the properties of cardiac muscle?

Back 4

- Contracts all the time

- Controls itself with help from nervous and endocrine systems

- Fibres are forked (bifurcated) with discs in between them (intercalated discs)

- Fibres each have single cell nuclei

Front 5

What are the properties of skeletal muscle?

Back 5

- Facilitates movement when it contracts

- Voluntary muscles (consciously controlled)

- Fibres have multiple nuclei

- Fibres are parallel and cylindrical

Front 6

Non-striated muscle

Back 6

- Consists of smooth muscle

- Contracts gently to push the food through the digestive system

- Involuntary

- Found in the walls of blood vessels and some internal muscular organs (e.g. Urinary bladder and uterus)

- Individual smooth muscle cells are tapered and have single nuclei

- Fibres are arranged on sheets of overlapping fibres

Front 7

What connective tissue covering surrounds each muscle belly of skeletal muscle?

Back 7

The epimysium

Front 8

What are the bundles of fibres that make up every skeletal muscle belly?

Back 8

Fascicles.

Front 9

What connective tissue surrounds each fascicle?

Back 9

Perimysium.

Front 10

What are the smaller units that make up the fascicles?

Back 10

Myofibres.

Front 11

What is the plasma membrane that encloses the muscle fibres called?

Back 11

The sarcolemma.

Front 12

What is the connective tissue that surrounds each cell?

Back 12

The endomysium.

Front 13

What happens when a nerve impulse is conducted through a muscle cell?

Back 13

Various ions move in and around the cell, allowing protein filaments to "slide" past each other.

Front 14

Which organelles make up a system of channels that surround the myofibrils within the muscle cell?

Back 14

The satcoplasmic reticulum.

Front 15

What are sarcomeres?

Back 15

The smallest functional units of a muscle.

Front 16

What are sarcomeres composed of?

Back 16

Filaments of thr proteins actin and myosin.

Front 17

What are actin and myosin responsible for?

Back 17

Muscle contraction.

Front 18

Actin

Back 18

Thin filament with other proteins wrapped around it.

Front 19

Myosin

Back 19

Thick filament with globular heads at one end.

Front 20

What are the three ways that muscles can contract?

Back 20

1. Concentrically

2. Eccentrically

3. Isometrically

Front 21

Concentric contraction

Back 21

Actin and myosin shorten the length of the muscle (towards the ceiling in anatomical position)

Front 22

Eccentric contraction

Back 22

Actin and myosin is sliding, but sarcomere is lengthening. E.g. Lowering your forearm after lifting it to your upper arm.

Hint 22

Eccentric = earth - load is moving towards the earth

Front 23

Isometric contraction

Back 23

Muscle is contracting, but there is no visible movement. Myosin is gripping the actin, but the sarcomeres do not visibly change length.

Hint 23

Iso = equal and metric = length, therefore, iso + metric = muscles not changing length

Front 24

How many skeletal muscles are there in the human body?

Back 24

650.

Front 25

What are the seven reason for muscle names?

Back 25

1. Shape

2. Way the fibres run

3. Location

4. Amount of muscles that make up a group

5. The relative position of the muscle

6. The size or length

7. Action

Front 26

What are the four main functions of skeletal muscles?

Back 26

1. Allow movement

2. Maintain posture

3. Stabilise joints

4. Produce heat

Front 27

What are the five golden rules of skeletal muscle activity?

Back 27

1. All muscles cross at least one joint.

2. Typically, the bulk of the muscle lies proximal to the joint crossed.

3. All muscles have at least two attachments: the origin and the insertion.

4. During contraction, the muscle insertion moves towards the origin.

5. Muscles can only pull, they never push.