Post on 06-Jan-2016
description
Moving the Body
Muscles and Bones
I. Bones
A. Functions
- site of formation of red blood cells
- offers support and structure for the body
- protection of internal organs (brain, heart, lungs)
- aids in locomotion (movement)
Bones (contd.)
B. Parts of Bone- bone is made of both living
and non-living materials1. Periosteum - thin, living
membrane covering the outer surface of bone
- has many blood vessels in it to carry nutrients and oxygen to the living parts of the bone
- bone cells are called osteocytes
Bones (contd.)
- bone is also made of non-living components - calcium and phosphorous
- give bones strong, rigid, structure
- not enough calcium in diet can cause rickets (in children) and osteoporosis (in older people)
Bones (contd.)
2. Spongy Bone - bone with many open spaces
- found towards the ends of long bones
- made of a hard network of minerals
3. Compact Bone- made of minerals, osteocytes, blood vessels, nerves, and elastic fibers
- dense, hard, inner part of bones
Bones (contd.)
4. Bone Marrow - found at center of bone
- gel-like material - makes red blood cells- 2 types of bone marrowa. yellow marrow - found in
long part of the bone, mostly made of fat
b. red marrow - found in spongy bone
- where red blood cells are made
Bones (contd.)
5. Cartilage - connective tissue that serves as a cushion and lubricant where bones meet
C. Bone Strength- bones are able to resist
high amounts of pressure- are lightweight, but strong
due to minerals- spongy bone serves as a
natural shock absorber
Bones (contd.)
D. Bone Development- most bones start off as
cartilage (when you are a baby)
- as you grow older, the process of ossification occurs - converting cartilage into bone
- eventually, almost all of the cartilage in your skeleton is replaced by bone
Bones (contd.)
- some animals have skeletons composed almost entirely of cartilage
- cartilaginous fishes - sharks and rays
- only bones that are fully formed whn you are born are the three small bones in the inner ear (hammer, anvil, and stirrup)
II. Joints
A. Joint - a place where two or more bones meet
- 6 types of joints1. Ball and Socket - allows
for circular movement (ex.: hip, shoulder)
2. Hinge Joint - allows for back and forth movement (ex.: elbow, knee, fingers)
Joints (contd.)
3. Pivot Joint - allows one bone to pivot past another
- allows for rotating movement (ex.: radius and ulna in forearm)
4. Gliding Joint - allows bones to glide past one another
- relatively little movement (ex.: vertebrae (backbone))
Joints (contd.)
5. Fused (Immovable) Joint - no movement (ex. Skull, pelvis)
6. Saddle Joint – allows for side to side and back and forth motion
(ex.: thumb)
Joints (contd.)
B. Connecting Bones- bones are connected to one
another by ligaments- like rubber bands - type of
connective tissue- in between bones, there is a
layer of synovial fluid - which cushions and lubricates the joint
- secreted by cartilage- cartilage covers ends of
bones to keep them from rubbing together
III. Muscles
- help to move bones like levers
A. 3 Types of Muscle1. Skeletal Muscle (Striated
Muscle)- voluntary - under your
direct, conscious control- controls, walking, talking,
etc- cells have no visible
nucleus
Muscles (contd.)
2. Smooth Muscle
- involuntary muscle
- no direct, conscious control
- controls body functions that always need to keep running
ex.: breathing, digestion
Muscles (contd.)
3. Cardiac Muscle - heart muscle
- only found in heart
- involuntary muscle - not under direct, conscious, control
- controls heartbeat
Muscles (contd.)
B. Muscle Movement1. Flexors and Extensors- muscles always occur in
pairs- muscles can only
shorten, or contract - need a partner muscle
moving in an opposite direction to stretch muscle out after it has been contracted
Muscles (contd.)
- like Newton's 3rd Law - for every actions, there is an equal and opposite reaction
a. flexor - the muscle that contracts and causes movement to occur at a joint
b. extensor - muscle that extends the muscle and bone
Muscles (contd.)
- causes bone to straighten out after they have been moved at the joint
muscles contract and relax in pairs
- important pairs of muscles in the body:
ex.: biceps and triceps (in upper arm)
quadriceps and hamstrings (in thigh)
Muscles (contd.)
2. Muscle Organization- muscles are made of
bundles of string-like tissue called fibers
- fibers are made of smaller tissues called filaments
- 2 types of filamentsa. actin b. myosin
Muscles (contd.)
- filaments make and break chemical bonds
- what causes muscles to be able to shorten (contract) and lengthen (extend)
- muscles are connected to bones by tendons