Grade 12 Kinesiology - Unit 1 Test Review

5 Types of Bones + example of each

1. Long bones (e.g. femur)

2. Short bones (e.g. carpals)

3. Flat bones (e.g. skull)

4. Irregular bones (e.g. vertebrae)

5. Sesamoid bones (e.g. patella)

Appendicular vs Axial Skeleton

appendicular: bones of the limbs

axial: skull, vertebrae, ribs, sternum

Does the appendicular or axial skeleton allow for more movement?

appendicular

Compact Bone vs Cancellous Bone

compact: thick part of the bone, responsible for structural integrity

cancellous: filled with marrow in its cavities, responsible for shock absorption

Epiphyseal Plate vs Epiphyseal Line

epiphyseal plate: “growth plates,” occur at various locations in the epiphysis

epiphyseal line: occurs when epiphyseal plates have fused together after growth has stopped

Epiphysis

ends of long bones

Diaphysis

shaft of long bones

Articulating Cartilage

located on both ends of bone

allows for smooth movement while protecting the ends of the bones

Cartilage does not have any _____ supply or _____ endings. _____ supply is crucial to heal properly.

blood, nerve, blood

How can you know if a bone has stopped growing?

if you take an x-ray and you can see their epiphyseal line (means epiphyseal plates have fused and growth has stopped)

How does compact bone form?

• begins as cartilage

• osteoblasts deposit osteoid into the cartilage

• inorganic salts are deposited into the osteoid

• osteoid hardens creating the bone

How does cancellous bone form?

• begins as fibrous membranes

• osteoblasts release osteoid into the membranes which forms a sponge-like bundle of fibres

• cancellous bone formation develops outwards from these centres in the membrane

Osteocytes

bone cells

Osteoblasts

bone forming cells

Osteoclasts

bone-destroying cells

Ossification

production of new bone

Ossification Centers/Epiphyseal Plates

places where growth of bone occurs

Bone Remodelling

further development of the bone in which it is continuously created and destroyed

• process is most active during the early years of human growth

Remodeling of bone begins to decline at around age __.

35

After 40, there is about a _-__% loss of bone mass per decade of life.

5-10%

How do Bones Heal?

same way when bone is growing

callus is formed at the site of the break, which forms a new true bone as strong (or even stronger) than the one before it

Stages of Bone Healing

1. Hematoma (swelling with blood)

2. Soft callus formed

3. Hard callus formed

4. Remodelling (old bone tissue is absorbed and replaced with new bone tissue)

Callus

temporary structure that forms when a bone is healing from a break

3 Types of Muscle Tissue

1. Smooth muscle

2. Cardiac muscle

3. Skeletal muscle

Smooth Muscle

• surround internal organs

• contract slowly

• involuntary

• fatigue resistant

• have spindle shaped fibres

• are arranged in dense sheets

Cardiac Muscle

• only found in the heart

• involuntary

• very fatigue resistant

• striated (striped) fibers

• arranged in layers

Skeletal Muscle

• striated (striped) in form

• not fatigue resistant

• voluntary

Skeletal muscle is also known as ________ muscle.

striated

Antagonistic Muscles

pairs of opposing muscles that perform the exact opposite movement of each other, composed of:

Agonist - prime mover (for that specific movement)

Antagonist - opposing mover

e.g. biceps brachii and triceps brachii are an antagonistic muscle pair

Stabilizers

muscles that provide support to hold a joint in place so antagonistic muscle pairs can perform movements

Tendon

connect muscle to bone

Ligament

connect bone to bone

Sensory vs Motor Pathways

sensory: collect info from sensors throughout the body + transmits that info to the brain

motor: conduct signals to activate muscle contractions for movement

All-or-None Principle

all the muscle fibres in a motor unit need to pass the threshold (of enough acetylcholine/electrical charge) for the contraction to happen

when a motor unit is stimulated to contract, it will do so to its fullest potential every single time.

there is either a full contraction or NO CONTRACTION AT ALL

Central Nervous System (CNS)

brain + spinal cord

Peripheral Nervous System (PNS)

sensory + motor pathways

Muscle Twitch

single nerve impulse + the resulting contraction

True or False: one motor neuron may be responsible for stimulating several muscle fibres.

True

Motor Unit

a group of muscle fibres that are contracted via the same motor neuron

All muscle fibres of one motor unit are always the ____ muscle type.

same

Muscles needed to perform precise movements generally consist of ____ motor units and a ___ muscle fibres.

many, few

Muscles needed to perform less precise movements are carried out by muscles of _____ motor units with ____ fibres per unit.

fewer, many

The Neuromuscular Junction has the

has the:

• axon

• axon terminal

• synaptic cleft

• receptor

• neurotransmitter (acetylcholine)

Axon

carries nerve signal

Axon Terminal

where the nerve and muscle meet

What is the neurotransmitter used for muscle contractions?

acetylcholine

Dendrite

receives signals

Summary of Muscle Contraction (sliding filament theory)

1. signal from brain/spinal cord

2. electrical impulse sent along neurons down the axon

3. signal reaches motor unit

4. signal moves through dendrite + axon towards axon terminal

5. signal triggers vesicles containing NT acetylcholine to release NT across synaptic cleft

6. acetylcholine binds with receptors on muscle

7. binding with receptors triggers calcium to be released by sarcoplasmic reticulum

8. calcium binds to troponin found on actin

9. causes tropomyosin to move, exposing myosin binding sites

10. myosin heads have ATP bonded, which break down to ADP + P_i, causing myosin heads to move and bind with binding sites on actin

11. cross bridges have formed

12. myosin moves the actin, "shortening the muscle”

13. another ATP is used to break the cross bridge between actin + myosin

14. (so long as calcium is bonded) contraction continues

Concentric Contractions

muscle fibres shorten

Eccentric Contractions

muscle fibres lengthen

Isometric Contraction

muscle fibres do not change in length

Isotonic Exercise

controlled shortening + lengthening of the muscle

Isometric Exercise

muscle fibres maintain a constant length and there is no motion

Isokinetic Exercise

using machines to control the speed of contractions

Epimysium

sheath enveloping entire muscle

Perimysium

sheath of connective tissue that covers fascicle

Fasicle

bundle of muscle fibres

Endomysium

sheath of connective tissue surrounding each individual muscle fibre

Myofibrils

make up the muscle fibres

Sarcolemma

muscle membrane

beneath the endomysium

contains the muscle fibre’s cytoplasm (sarcoplasm)

Sarcoplasm

muscle fibre’s cytoplasm

in the sarcolemma

Sarcomeres

repeating units of skeletal muscle that contain actin and myosin

makes up a myofibril

Sarcoplasmic Reticulum

network of web-like structures that run up and down the sarcomeres providing calcium for muscle contraction

Summary of Anatomy of Skeletal Muscle

(superficial → deep)

1. epimysium

2. perimysium

3. endomysium

4. muscle fibre

5. sarcolemma

6. sarcoplasmic reticulum

7. myofibrils → sarcomeres

8. actin/myosin

Myosin and Actin

thick and thin protein filaments (respectively) within the myofibrils

make up the muscle fibres at a cellular level

Myosin

made up of a “head” and a “tail” and looks like a golf club

head is attachment site for actin

Actin

has 2 proteins: troponin + tropomyosin

Troponin vs Tropomyosin

troponin: has binding site for calcium

tropomyosin: “stringy-looking” cord-like structure that covers the binding site for actin

When a muscle is relaxed, ___________ in actin covers the binding site (preventing myosin from latching on). To contract the muscle, _______ needs to be released to bind to ________, which removes ___________ from the binding sites, allowing myosin to latch on and pull the actin.

tropomyosin, calcium, troponin, tropomyosin

Musculoskeletal System

system that allows for movement

Sarcomeres are made up of 2 types of protein myofilaments:

1. Actin (thin filament)

2. Myosin (thick filament)

Each myosin is surrounded by _ actin filaments.

6

What is the '“trigger mechanism” for muscle contraction? Why?

release of calcium ions

• they bind to troponin which causes tropomyosin to stop blocking the binding sites on actin, so myosin can bind to actin and cause muscle contraction

Terminal Cisternae

releases calcium ions into the sarcoplasm

sacs that form part of the sarcoplasmic reticulum

Myosin Cross Bridge

temporary attachment of myosin heads to actin

After the myosin heads pull the actin, another ___ is attached to the myosin heads to replace the previously used one. This secondary ___ triggers the release of the myosin head from the attachment sites. The ATP is then immediately broken down into ___ & a __ molecule again, to repeat the whole process over again if calcium is still attached to the actin

ATP, ADP, P_i

Muscle contraction will continue until the calcium is released from actin and the re-uptake of the calcium ions into the ____________ _________ takes place.

sarcoplasmic reticulum

Repeatedly, myosin cross bridges attach, ______, detach and reattach in rapid succession. This process results in the sliding or overlap of the filaments, a shortening of the sarcomere, and what we see and know as muscle ___________.

rotate, contraction

sliding filament theory

sliding filament theory

Cross Bridge Formation

head of the myosin filaments temporarily attaches themselves to the actin filaments

Cross Bridge Movement

myosin pulls and rotates actin

Sarcomeres should be at an optimal distance apart for muscle contraction. This optimal distance is 0.00__-0.00__ micrometres.

If the sarcomeres are stretched further apart than optimal distance → _____ cross bridges can form → ____ force produced.

If the sarcomeres are too close together → cross bridges interfere with one another as they form → ____ force produced.

19, 22

fewer, less

less

Excitation-Contraction Coupling

converting chemical E (ATP) into mechanical E

Joints

points at which bones connect

What system are joints part of?

articular system

Articular System

joints + their surrounding tissues that make connections between bones and muscle to make movement possible

Why are joints highly susceptible to injury?

because they are points of great stress (since they are involved in all our movements)

3 Types of Joints

1. Fibrous Joints

2. Cartilaginous Joints

3. Synovial Joints

Fibrous Joint (+ example)

bones connected by fibrous tissues

allow NO MOVEMENT

ex. sutures between the bones of the skull

Cartilaginous Joint (+ example)

bones connected by cartilage

SLIGHT MOVEMENT possible

ex. symphysis pubis

Synovial Joint (+ example)

bones ‘connected’ by synovial fluid, cartilage, and ligaments

MUCH MOVEMENT possible

ex. knee joint

Characteristics of Synovial Joints

• articulating cartilage

• joint capsule

• synovial membrane

• fibrous capsule

• joint cavity

• bursae

• intrinsic ligaments

• extrinsic ligaments

Articulating Cartilage (Synovial Joints)

on the ends of bones

protects the ends of the bones, acts as shock absorber

Joint Capsule (Synovial Joints)

fibrous structure that consists of the synovial membrane and fibrous capsule

Synovial Membrane vs Fibrous Capsule (Synovial Joints)

synovial membrane - membrane that allows certain nutrients to pass through (more permeable, functional)

fibrous capsule - keeps synovial fluid from leaking (less permeable, structural)

Joint Cavity (Synovial Joints)

located between the articulating surfaces

houses the synovial fluid

Synovial Fluid Purpose

to lubricate the synovial joint (reduce friction) and provide nutrients for the articulating cartilage

Bursae (Synovial Joints)

small, flattened fluid sacs found at the friction points between tendons, ligaments and bones

Intrinsic Ligaments vs Extrinsic Ligaments (Synovial Joints)

intrinsic - thick bands of fibrous connective tissue that help thicken and reinforce the joint capsule

extrinsic - separate from the joint capsule, helps to reinforce joint by holding bones together

Types of Synovial Joints

• gliding joint

• hinge joint

• pivot joint

• ellipsoid joint

• saddle joint

• ball-and-socket joint