Bones, Muscles and Joints

Question 1

Describe the structures of different muscle cells

Answer 1

Involuntary: Not striated, not branched, one nucleus per cell, and they are tapered at one end

Voluntary: Striated, many nuclei per cell, not branched

Cardiac: Striated, branched cells that make up a mesh-like framework and have several nuclei per cell

Question 2

Tissue that line organs are called __________

Answer 2

Epithelia: ciliated epithelial cell and squamous epithelial cells

Question 3

Functions of the skeletal system

Answer 3

• Protection
• Support, framework
• Movement
• Makes some components of the blood (in larger bones: sternum, femur, and pelvis)

Question 4

Structure of bones:

Answer 4

• Rigid material (calcium (phosphate) salts) - resist bending and compression forces
• Made up of osteocytes wich along with protein fibres stop the bone from being too brittle and easily broken
• Outside of the bone is made up of a hard material called the compact bone
• The middle of the bone is made up of spongy bone (fewer calcium salts) with bone marrow running through it
• Longer bones have a hollow cavity with bone marrow running through it
• The tough membrane: periosteum covers the outside of the bone.
• Cartilage is present at the ends of long bones made up of chondrocytes; it is tough but flexible

Question 5

How does bone grow?

Answer 5

Ossification: A long bone has regions of cartilage close to the ends of the bone that grow and become ossified

Question 6

Describe the microscopic structure of compact bone:

Answer 6

• Made up of osteocytes
• Arrange themselves in concentric rings called Haversian systems surrounding a Haversian canal containing blood vessels and nerves
• Osteocytes secrete calcium phosphate salts which (along with protein fibres) make up the bone matrix

Question 7

What is cartilage?

What is its function?

Answer 7

• Cartilage is present at the ends of long bone
• It’s a tough but flexible tissue made up of chondrocytes
• They secrete a matrix containing various types of protein fibres
• Function: to provide cushioning between two bones at a joint and as a shock absorption surface

Question 8

What 3 features should movable joints have?

Answer 8

• Lack of friction
• Shock-absorbing surface
• Need to ensure that bones stay together and don’t dislocate

Question 9

Structure of movable joints:

Answer 9

• They contain a synovial fluid secreted by the synovial membrane that lines the space in the middle of the joint (oily: lubrication)
• An articulating surface covered with a smooth layer of cartilage (strong but not brittle)
• The joint is surrounded by a tough fibrous capsule and held together by ligaments

Question 10

Features of ligaments:

Answer 10

• Attach one bone to another bone
• Composed of tough fibres
• Tensile strength (strength to resist stretching)
• Elastic

Question 11

Cranium consists of ___ bones

Answer 11

22

Question 12

Features of tendons:

Answer 12

• Attach muscle to the bone
• Tensile strength
• Inelastic (don’t stretch when muscles contract)

Question 13

What are biceps and triceps?

Answer 13

Biceps are the muscles at the front of your upper arm, that flex the arm
Triceps are the muscles at the back of your upper arm, that extends the arm

Question 14

What are the origin and insertion of a muscle?

Answer 14

The origin is the place where a muscle is attached to a bone that remains stationary when the muscle contracts
The insertion is the place where a muscle is attached to a bone that moves when the muscle contracts

Question 15

Which antagonistic pairs are used in running?

Answer 15

Biceps femoris (flexes the knee joint) and quadriceps (extending the knee)

Question 16

The main muscle responsible for bending the spine is ____________

Answer 16

Rectus muscle

Question 17

How does the spine bend?

Answer 17

The bones ta each joint can be slightly pulled closer together or move further apart to allow a slight bending movement. Because of this slight bending movement in each joint, the entire spinal column can bend

Question 18

What structures in the vertebrae are for (a) muscle attachment and (b) rib attachment?

Answer 18

(a) Neural spines and transverse process

(b) Facet

Question 19

The lumbar vertebrae have the strongest centrum to _________

Answer 19

Support all the body’s weight

Question 20

Role of protein filaments in muscle contraction:

Answer 20

• Thick and thin filaments

- When muscle contracts the thin filaments slide past the thick filaments, making the fibres shorter.

Question 21

Changes that take place to provide muscles with the increased demand for oxygen and glucose during exercise

Answer 21

• Increased breathing rate
• Increased heart rate
• Blood diverted from gut to muscles
• Vasodilation and sweating

Question 22

A state of partial muscle contraction is called ___________. How does it help?

Answer 22

Muscle tone helps keep our muscles taut but not enough to cause movement and it keeps us upright when we stand or sit

Question 23

What is osteoporosis?

More common in ________

Treatment?

Answer 23

A medical condition in which the bones lose too much calcium salts and become porous and less dense therefore weak and are prone to fractures

More common in women after menopause due to change in hormone levels

A good diet and Vitamin D supplements and treatment with hormones