Unit 1 - Applied Anatomy

Question 1

What is a joint?

Answer 1

A joint occurs where two or more bones articulate.

Question 2

What are the 3 types of joints?

Answer 2

Fibrous - connected by dense connective tissue, fixed/immovable, found in skull
Cartilaginous - bones are entirely joined by cartilage, less movement than synovial, found in spine
Synovial - between bones that move against each other (limbs)

Question 3

Explain the structure of muscles (more magnified).

Answer 3

Muscle fibers made of myofibrils, myofibrils surrounded by sarcoplasmic reticulum which stores calcium, myofibrils broken down into repeating segments (sarcomeres consist of actin and myosin).

Question 4

Epimysium

Answer 4

outer layer, covers entire muscle

Question 5

Perimysium

Answer 5

bundles of muscle fibers

Question 6

Endomysium

Answer 6

Layer of fascia that surrounds individual fibres

Question 7

Myofibril

Answer 7

threads found in striated muscle cells

Question 8

Sarcomere

Answer 8

Structural unit of a myofibril in striated muscle cells

Question 9

Actin and Myosin

Answer 9

Protein forms filaments of muscle cells

Question 10

Muscle Fibre

Answer 10

composed of myofibrils

Question 11

Sliding Filament Theory

Answer 11

1. Sarcoplasmic Reticulum stimulated to release calcium ions
2. Calcium ions bind to troponin thus moving both troponin and tropomysium (same structure) to expose binding site on actin filament
3. ATP uses energy to connect myosin head to actin filament (creating cross-bridge) while breaking down into ADP, phosphate ion is produced.
4. Power stroke occurs, Z-lines come closer to one another, making the H-zone smaller (this is the contraction as actin filaments are closer together and sarcomere has shortened)
5. Cholinesterase breaks down Ach and the muscle fiber relaxes.

Question 12

Axial Skeleton

Answer 12

Provides protection and support for vital organs, 80 bones. Also surface for attachment of muscles. Strong and limited movement, fused.
e.g.: ribs, sternum, cranium, vertebrae

Question 13

Role of cholinesterase

Answer 13

Allows muscle to relax by breaking down Ach in 5 milliseconds. Repolarizes membrane immediately.

Question 14

Anatomical terminology

Answer 14

Superior - higher
Inferior - lower
Posterior - behind
Anterior - Front
Proximal - close to origin
Distal - further from origin
Medial - close to middle
Lateral - further from middle

Question 15

4 Types of Bones

Answer 15

Long - long, slightly curved for strength (arms and leg bones)
Short - small, (tarsals, carpals)
Flat - thin and flat, protects vital organs (skull, sternum, scapula)
Irregular - (vertebrae, sacrum)

Question 16

Muscle Fibre Type 1

Answer 16

• slow twitch
• red due to large volumes of myoglobin, more blood vessels
• very resistant to fatigue (high prevalence of mitochondria)
• high capillary density (increased oxygenation)
• low ATP stores
  low glycogen stores
• longer to contract, not as explosive (long-distance)

Question 17

Types of Muscle

Answer 17

Smooth - (in walls of internal organs, involuntary) spindle-shaped, non-striated, single nucleus, no tension sensors or stretch receptors
Cardiac - (in walls of heart, involuntary) striated, branched, single nucleus, no tension sensors or stretch receptors
Skeletal - (attached to muscle via tendons, voluntary) striated, multinucleated, cells bound together by fascia, tension sensors or stretch receptors

Question 18

Appendicular Skeleton

Answer 18

Locomotion, balance and attachment. 126 bones. (clavicle, humerus, femur…)

Question 19

Reciprocal Inhibition

Answer 19

Muscle must relax on one side of joint (antagonist) to allow for a muscle on the other side (agonist) to contract effectively. For safety otherwise a muscle tear would likely occur.

Question 20

Role of Acetylcholine (Ach)

Answer 20

-increases membrane permeability to sodium ions
-opens motor end plate channels
-released from nerve endings and binds to receptors on muscle surface
-causes depolarization, enabling calcium to be released

Question 21

Isotonic Muscle Contraction

Answer 21

Change in length
Concentric - muscle shortens
Eccentric - muscle lengthens

Question 22

Isometric Muscle Contraction

Answer 22

No change in length when contracting (plank, handstand)

Question 23

Isokinetic Muscle Contraction

Answer 23

develops tension and changes length at a constant speed (cycling, breastroke)

Question 24

Delayed Onset Muscle Soreness (DOMS)

Answer 24

Pain and stiffness felt in muscles 24-72 hours after strenuous or unaccustomed exercise. Associated with inflammatory reactions, overstretching, overtraining and structural muscle damage. Can be prevented/minimized by reducing the eccentric component, gradually increasing intensity. Can be produced by micro tears, osmotic pressure, overstretching, etc.

Question 25

Origin

Answer 25

Attachment of a muscle tendon to a stationary bone

Question 26

Insertion

Answer 26

Attachment of a muscle tendon to a moveable bone

Question 27

Muscle Fiber Type 2a

Answer 27

-fast oxidative fibres
- red due to large no. of mitochondria and myoglobin
- more prone to fatigue
- fast, strong muscle contractions (med force and speed)
(mile run, swimming, cycling)

Question 28

Muscle Fiber Type 2b

Answer 28

• anaerobic
  -highly developed sarcoplasmic reticulum
  -high ATP stores
• fast glycolytic fibers
  white due to low levels of myoglobin and mitochondria
  -rapid fatigue
  -shot, fast bursts of power
  (sprinting, weightlifting)

Question 29

Functions of connective tissues

Answer 29

Cartilage - coats surface of bones in joints. shock absorber, keeps motion fluid (bone to bone)
Tendon - allows flexion and extension (muscle to bone)
Ligament - holds structures together, stability for synovial (bone to bone)

Question 30

Types of Synovial Joints

Answer 30

Hinge - up and down (elbow)
Ball and Socket - rotation (shoulder)
Condyloid - front and back, nearly full rotation (wrist and fingers)
Pivot - single axis (neck)
Gliding - all directions, limited mobility (vertabrae)
Saddle - multiple axis (thumb)

Question 31

Structure of a Long Bone

Answer 31

epiphysis - rounded end
spongy bone - ends, lighter + less dense
articular cartilage - smooth white tissue covers ends
diaphysis - long central shaft
compact bone - dense hard external layer
bone marrow - soft spongy tissue center of bones
marrow cavity - central cavity
blood vessel - controls aspects of bone formation
periosteum - ligaments and tendons attach to this dense layer of connective tissue

Question 32

Characteristics common to muscle tissue

Answer 32

Contractibility - ability to shorten
Extensibility - ability to shorten
Elasticity - return to normal size
Atrophy - waste away of muscle tissue
Hypertrophy - increase in size
Controlled by nerve stimuli - requires an impulse
Fed by capillaries - blood will be redistributed to muscles when they are working

Question 33

Features of a Synovial Joint

Answer 33

Articular cartilage - covers ends of bone
synovial membrane - holds synovial fluid in place
synovial fluid - provides smooth movement
bursae - fluid-filled sacs, reduce friction
meniscus -shock absorber
ligament
articular capsule - surrounding a synovial joint