Unit 1 - Anatomy and physiology for health and exercise - Skeletal system

Question 1

What do bones consist of?

Answer 1

Bone consists of a mixture of water, protein and mineral salts, the latter of which constitutes roughly 50% of its structure.

Question 2

What is bone strength the rsult of?

Answer 2

Bone strength is the result of a combination of the hardness of the minerals combined with the tensile properties of collagen.

Question 3

What is collagen derived from?

Answer 3

Protein.

Question 4

What happens to a bone if it had too little of collagen?

Answer 4

The bone would shatter like an eggshell.

Question 5

What happens if the bone had too little of the mineral salts?

Answer 5

The bone will bend like a piece of rubber.

Question 6

What is the process of bone formation called?

Answer 6

Ossification.

Question 7

What does the hardening and growth process of bones involve?

Answer 7

Replacing a cartilage “framework” with mineral salts.

Question 8

Why are bones of young children softer than those of adults?

Answer 8

Because they still contain significant proportions of cartilage.

Question 9

When is the hardening process of bone complete?

Answer 9

It may not be complete until 30 years of age.

Question 10

In early life, what does the ossification emphasize on?

Answer 10

The emphasis of ossification is very much on bone growth and bone hardening.

Question 11

In adulthood, what does the ossification emphasize on?

Answer 11

The emphasis of ossification is more geared towards replacing and maintaining existing bone material.

Question 12

What are the primary cells involved in bone growth?

Answer 12

Osteoblasts.

Question 13

What is the function of osteoblast?

Answer 13

Its function is to replace worn out or damaged bone tissue.

Question 14

Their activity is coordinated with what other cells?

Answer 14

Osteoclasts, which remove the old bony tissue.

Question 15

Does the maintenance of a healthy skeletal system happen in every bone equally with osteoblast and osteoclast?

Answer 15

No, it can vary according to the region of bone concerned; then end of the femur, for example, can be completely remodelled every few months, which contrast with the bone shafts, which may never be fully remodelled.

Question 16

What other factors will remodelling of bone tissue tend to follow?

Answer 16

The lines of stress placed upon the bone, such as exercise and habitual posture.

Question 17

Give an example of bad remodelling of bone tissue.

Answer 17

Incorrect exercise technique coupled with generally poor alignment will lead to a remodelling process that may reinforce the predominating bad posture.

Question 18

What is bone formation predominantly regulated by in the pre-puberty years?

Answer 18

Human growth hormone (HGH), produced by the pituitary gland (located in the brain).

Question 19

What is bone formation regulated by at puberty?

Answer 19

Testosterone produced by the male testes and oestrogen produced by the female ovaries.

Question 20

In what important functions is calcium involved in?

Answer 20

Apart from providing the skeletal system with rigidity, it is also involved in muscular contraction, the transmission of nervous impulses and regulating fluid balance.

Question 21

Why do bones have calcium reservoirs?

Answer 21

The calcium reservoirs in bones can either take up or release calcium depending on the body’s needs.

Question 22

What happens if calcium is scarce?

Answer 22

It will be withdrawn from the bones, which is why diets that are chronically low in calcium tend to increase the risk of osteoporosis.

Question 23

How is osteoporosis, brittle bone disease, caused?

Answer 23

By an imbalance in the delicate balance of the bone remodelling, whereby osteoblast activity decreases causing a drop in bone growth. This leads to a gradual loss in bone density and ultimately gives rise to a skeletal system that is unable to withstand the forces placed upon it.

Question 24

What may cause an imbalance in osteoblast and osteoclast activity?

Answer 24

there may be a number of causes of the condition; however one of the biggest is the drop in oestrogen levels associated with the menopause.

Question 25

Why are women more prone to osteoporosis than men?

Answer 25

The drop in oestrogen levels associated with the menopause makes woman significantly more likely to develop the condition than men. In men, a proportion of circulating testosterone is converted into oestrogen and this is thought to provide men with significant protection against loss of bone mass.

Question 26

What other risk is there to develop osteoporosis in females?

Answer 26

Low calorific intake and/or overtraining also increase the risk of osteoporosis in females by depleting body fat stores which are one of the primary sources of oestrogen. Poor quality diets which are lacking in or have an imbalance of minerals and vitamins also increase the risks by limiting the availability of calcium

Question 27

List Osteoporosis risk factors.

Answer 27

→ female sex - due to a drop in oestrogen levels → calcium deficiency - through poor diet or poor absorption → lack of exercise → smoking - causes a drop in oestrogen levels → family history → certain drugs, such as alcohol which interrupt normal hormonal and calcium regulation → low body fat → overtraining

Question 28

In what two forms does bone tissue come in?

Answer 28

Compact and cancellous.

Question 29

Describe a compact bone.

Answer 29

→ It has a relatively high density of bone matter. → It forms the external surfaces of bones, predominates in the shafts of long bones and serves to resist compressive forces.

Question 30

Describe a cancellous bone.

Answer 30

* It is relatively more porous than a compact bone and if viewed closely has a spongy appearance. * It predominates in the interior of bones and especially at bone ends (ephiphyses).

Question 31

What are the spaces within the cancellous bone good for?

Answer 31

They form a vital function by housing red marrow, which is responsible for red blood cell production.

Question 32

Name the four shape categories of bones.

Answer 32

* Long bones * Short bones * Flat bones * Irregular * Sesamoid ("seed-like")

Question 33

Describe a long bone.

Answer 33

* They have a greater length than width and consist of a shaft with normally two extremities. * They contain mostly cancellous bone in their ephiphysis and more compact bone in their diaphysis. * They act principally as levers.

Question 34

Give examples for long bones.

Answer 34

* Humerus * Femur * Fibula * Tibia * Ulna * Radius * Metacarpals * Metatarsals * Phalanges

Question 35

Describe a short bone.

Answer 35

They have a cubed appearance and are predominantly cancellous bone with an outer shell of compact bone.

Question 36

Give examples for short bones.

Answer 36

* Carpals (except for the pisiform - sesamoid) | * Tarsals (except for the calcaneus - irregular)

Question 37

Describe a flat bone.

Answer 37

They are thin cancellous bones sandwiched between two compact layers affording protection or large areas for muscle attachment.

Question 38

Give examples for flat bones.

Answer 38

Scapula, cranial bones, costals, sternum and ilum.

Question 39

Describe an irregular bone.

Answer 39

It is from complex shapes and cannot be classified in the

Question 40

Give examples for irregular bones.

Answer 40

Vertebrae.

Question 41

Describe sesamoid bones.

Answer 41

They develop within particular tendons at a site of friction or tension. They serve to reduce wear and tear in the tendon and increase the leverage of muscle by moving the tendon away from the fulcrum.

Question 42

Give examples for sesamoid bones.

Answer 42

Patella (kneecap) and pisiform (carpal bone).

Question 43

What are the epiphysis?

Answer 43

The bone ends.

Question 44

What are the epiphysis mainly comprised of?

Answer 44

Cancellous bone.

Question 45

What is housed in the epiphysis?

Answer 45

It houses much of the red marrow involved in red blood cell production.

Question 46

What is the diaphysis?

Answer 46

The shaft portion of a long bone.

Question 47

What is the diaphysis mainly comprised of?

Answer 47

Compact bone, although the inside of the shaft is hollow.

Question 48

What is the principal role of the diaphysis?

Answer 48

Support.

Question 49

What are epiphyseal plates?

Answer 49

The end of a long bone that is originally separated from the main bone by a layer of cartilage but that later becomes united to the main bone through ossification.

Question 50

What is the periosteum and what does it do?

Answer 50

The periosteum is a connective tissue that supports bone health and development. The thin tissue has two layers that function in different ways. The outer layer, known as the fibrous periosteum, allows for attachment of muscle tissue to the bone and provides pathways for blood and lymphatic tissues.

Question 51

What is the medullary cavity?

Answer 51

The medullary cavity (medulla, innermost part) is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow (adipose tissue) is stored; hence, the medullary cavity is also known as the marrow cavity.

Question 52

What is the articular (hyaline) cartilage?

Answer 52

Articular cartilage is hyaline cartilage on the articular surfaces of bones, and lies inside the joint cavity of synovial joints, bathed in synovial fluid produced by the synovial membrane, which lines the walls of the cavity.

Question 53

What is a joint?

Answer 53

It is defined as a meeting point of two or more bones.

Question 54

In which three types are joints traditionally categorised in?

Answer 54

Fibrous, cartilaginous and synovial.

Question 55

Describe fibrous (immovable) joints.

Answer 55

Fibrous joints are connected by dense connective tissue consisting mainly of collagen. These joints are also called fixed or immovable joints because they do not move. Fibrous joints have no joint cavity and are connected via fibrous connective tissue. The skull bones are connected by fibrous joints called sutures.

Question 56

Describe cartilaginous (slightly movable) joints.

Answer 56

→ some limited potential for movement. → articulating bones are connected by fibrocartilage. Examples: pubis symphysis and between the vertebral bodies. → provide moderate stability and some limited movement

Question 57

Describe synovial (freely movable) joints.

Answer 57

→ allow the "large" movements we associate with exercise → come in a variety of different configurations for different types of movements → has no connective tissue joining the articulating surfaces → joint space → ends of the bones are covered with a form of cartilage (hyaline cartilage) - to reduce friction between the moving surfaces

Question 58

By what are bony surfaces held together?

Answer 58

by a fibrous articular capsule (joint capsule) → flexible enough to allow plenty of movement → tough enough to support the joint where necessary

Question 59

What happens when sections of the joint capsule thicken?

Answer 59

They form ligaments which provide additional support to the joint.

Question 60

Where is the synovial membrane situated which secretes a lubricant called synovial fluid?

Answer 60

On the inner surface of the articular capsule.

Question 61

Describe the consistency of synovial fluid.

Answer 61

→ consistency of uncooked egg white → more viscous (thick) when the joint is inactive → fluidity increases as activity increases

Question 62

What does synovial fluid do?

Answer 62

→ serves to help lubricate the joint surfaces | → provides nutrients to the articular cartilage, which has a poor blood supply.

Question 63

Name the 6 categories of synovial joints.

Answer 63

1. ball and socket 2. hinge 3. pivot 4. gliding 5. saddle 6. ellipsoid

Question 64

What is a ball and socket joint?

Answer 64

→ allows for movement in almost any direction. | → hips and shoulders

Question 65

Describe a hinge joint.

Answer 65

→ like the hinges of a door → relatively simple structure → primarily allows either flexion or extension movements → example: elbow joint

Question 66

Describe a pivot joint.

Answer 66

→ allows rotation around an axis → example: 1. neck → the top 2 cervical vertebrae (the atlas and the axis) form a pivot joint allowing rotational movements of the head. 2. Forearm: the radius forms a pivot joint with the ulna, causing it to "radiate" around the ulna and allowing supination and pronation of the forearm.

Question 67

Describe a gliding joint.

Answer 67

→ typically flat articulating surfaces → joint action is a relatively simple sliding movement → ligaments generally restrict movement to forwards, backward and side-to-side movements. → example: patella and femur (patellofemoral), between the carpals and tarsals and the acromion process and clavicle (acromioclavicular).

Question 68

Describe a saddle joint.

Answer 68

→ resembles one upturned saddle resting on another → movements: back and forth + up and down → no rotation → example: articulation between the base of the metacarpal of the thumb and the trapezium (one of the carpals) - (carpometacarpal)

Question 69

Describe an ellipsoid joint.

Answer 69

→ similar to ball and socket but the shape is more oval in nature and consequently, movements tend to be restricted to side-to-side and back and forth → example: wrist joint between the radius and the carpals (radiocarpal) and metacarpals and phalanges (metacarpophalangeal) → sometimes referred to as a condyloid joint

Question 70

Give a general description of the vertebral column.

Answer 70

→ The vertebral column consists of a series of individual vertebrae that are arranged to form a strong and flexible rod, which provides the body with central support and facilitates movement. → Offers protection for the spinal cord → provides the means by which nerves are distributed throughout the body

Question 71

Of how many individual vertebrae consists the vertebral column and how many are located in which section?

Answer 71

``` → neck or cervical region = 7 → thoracic or chest section = 12 → lumbar = 5 → sacrum = 5 → coccyx = 4 ```

Question 72

What basic anatomical features do the vertebrae share?

Answer 72

→ Anterior: main vertebral body, which is a cylindrical bony disc. → the body provides the surface for the intervertebral discs to attach to and these form the main cartilaginous joints of the spine. → Posterior: series of bony projections which interlink with adjacent vertebra to form synovial facet joints. → A series of openings or foramen punctuate the vertebra, these allow nerves and blood vessels to pass through and out of the vertebral column.

Question 73

What are the intervertebral discs, that are sandwiched between the bodies of neighbouring vertebrae, composed of?

Answer 73

→ fibrocartilage shell, that surrounds a softer gel

Question 74

What is the primary function of intervertebral discs?

Answer 74

→ shock absorption, however, they are vulnerable to injury if the back is excessively loaded with poor alignment or if the back is held in a chronically poor posture

Question 75

The adult human spine has three major curvatures (excluding the sacrococcygeal), these are:

Answer 75

→ a posterior cervical curvature - a posterior concavity of the cervical spine → an anterior thoracic curvature - a posterior convexity of the thoracic spine → a posterior lumbar curvature - a posterior concavity of the lumbar spine

Question 76

Humans move or pick up objects via a basic system of levers. What is a lever?

Answer 76

A lever is a simple machine consisting of a rigid rod that moves or pivots around a fixed point (fulcrum).

Question 77

What are the three basic forms of lever?

Answer 77

``` 1st class levers, such as a seesaw. 2nd class levers, such as a wheelbarrow. 3rd class levers, the most common form of lever in the body. ```

Question 78

What is a 1st class lever?

Answer 78

Like on a seesaw, the fulcrum is located between the effort and the load. By moving the fulcrum closer to, or further away from the load; speed, range of movement and force generated will vary.

Question 79

Give examples for 1st class lever in the body.

Answer 79

Relatively scarce in the body: → triceps extending the forearm, → gastrocnemius and soleus plantarflexing the foot when it is off the ground.

Question 80

What is a 2nd class lever?

Answer 80

Example, wheelbarrow. the fulcrum and the effort are at opposite ends with the load placed in between. This arrangement produces plenty of force.

Question 81

What is a 3rd class lever?

Answer 81

Example, drawbridge. The fulcrum and the load are at opposite ends with the effort placed in between. Generally produces less force than the other forms of lever, but provides a much greater range of movement and speed.

Question 82

Name the three basic planes that represent anatomical cross-sections.

Answer 82

→ frontal plane: a vertical plane that divides the body into anterior and posterior parts → sagittal plane: a vertical plane that divides the body into left and right parts → transverse plane: a horizontal cross-section through the body separating the upper body from the lower body

Question 83

What is an axis of movement?

Answer 83

An axis is a line that passes through a plane, about which movement (rotation) occurs.

Question 84

What is a medial-lateral axis?

Answer 84

It passes through the sagittal plane: rotation would occur in the sagittal plane.

Question 85

What is an anterior-posterior axis?

Answer 85

It passes through the frontal plane: rotation would occur in the frontal plane.

Question 86

What is a longitudinal axis?

Answer 86

It passes through the transverse plane: rotation would occur in the transverse plane.