Mar 12 Muscle Physiology 1

Question 1

3 Types of Muscles in The Human Body

Type

Strait or smooth

Voluntary or involuntary

Where?

Answer 1

3 Types of Muscles in The Human Body

Skeletal
- straited tubular
- Voluntary control
- Used in Movement

Cardiac
- straited branched
- involuntary control
- Only in the heart

Smooth
- Smooth spindled
- involuntary control
- Internal organs

Question 2

Skeletal muscle types (2 things)

Answer 2

Types of contractions

• Circular, Convergent, and Paraellel
• Multipennate, Bipennate and Unipennate

Question 3

Types of muscle contractions

(Name 3)

Answer 3

Types of muscle contractions

Isometric - no movement
Eccentric - Bicep uncurl
Concentric - Bicep curl

Question 4

Skeletal muscle helps: (2 things)

Answer 4

Skeletal muscle helps:
* Regulate body temperature
* Secrete over 600 different proteins or products that impact your overall health and function.

Question 5

Exercise Myokines:

Answer 5

Exercise Myokines

*Myokines are proteins (or other secretory products) released from skeletal muscle that have beneficial effects on various tissues (sometimes called exerkines)

Question 6

Skeletal Muscle Structure

(3 things)

Answer 6

Skeletal Muscle Structure

• Each muscle is made of many long muscle cells called muscle fibers, which contain smaller parts called myofibrils. Endomysium covers each muscle fibers.
• Muscle fibers are grouped into bundles called fascicles and wrapped by Perimysium.
• The whole muscle is wrapped in a layer of connective tissue called the epimysium, and a layer called fascia surrounds and separates muscles from each other.

Question 7

Components of Muscles

(Name 5 and what they do)

Answer 7

Components of Muscles

Nucleus
- Governs cell behaviours and controls DNA

Sarcolemma
- Muscle cell membrane

Sarcoplasm
- Muscle cytoplasm, fluids that hold organelles

Sarcoplasmic Reticulum
- Calcium storage and release which is needed for muscle contractions

Myofibrils
- Contains filament where muscle contraction takes place, overlap to form sacromeres

Question 8

Sarcomere:
Muscles look striped (striated) because:

Answer 8

A sarcomere is the part of a myofibril between two cytoskeletal structures called Z-discs (also called Z-lines or Z-bands).

Muscles look striped (striated) because of the way thick (myosin) and thin (actin) filaments are arranged inside each sarcomere.

Question 9

The dark striated A band is made of: (2 things)

The lighter I bands are made of:

Answer 9

• The dark A band in a muscle fiber is made of thick myosin filaments, which stretch across the center of the sarcomere toward the Z-lines.
• These thick filaments are held in place at the center (called the M-line) by a protein called myomesin.
• The lighter I bands are made of thin actin filaments, which are attached at the Z-lines by a protein called α-actinin.

Question 10

Sarcomere:
However:

This is called the?

Answer 10

• A sarcomere is the space between two Z-lines. When a muscle contracts, this space gets smaller — the sarcomere shortens.
• But the thick (myosin) and thin (actin) filaments don’t actually get shorter. Instead, they slide past each other, pulling the Z-lines closer together.
• This is called the sliding filament theory. It explains how muscles contract by showing how the parts of the sarcomere move during contraction without changing the length of the filaments themselves.

Question 11

During contraction: (2 things)

Answer 11

• When a muscle contracts, the filaments don’t get shorter — they slide past each other. This sliding pulls the Z-discs closer together, shortening the sarcomere.
• The A band stays the same length because the thick (myosin) filaments don’t change. But the H zone and I band (areas with only thick or only thin filaments) get smaller.