Section: Skeletal System
Key Words: bone marrow, cartilage, ligament, mineral, red blood cell, skeletal system, skeleton
Essential Questions:
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•
•
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How does our skeletal system help us move?
How do bones, ligaments, and cartilage work together?
What are bones made of?
In addition to allowing movement, what else does our skeletal system help us do?
Skeletal System
Skeletal system – framework of the body
- contains all bones
- 5 characteristics:
o 1. Basic framework – provides support & structure
o 2. Provides protection for internal organs
o 3. Provides a place for muscles to attach
o 4. Produces new blood cells in center of the bones – marrow
o 5. Provides storage of minerals Ca & P
- Cartilage – at ends of bones
o Thick, smooth, slippery layer
o Provides flexibility @ joints
o Reduces friction on bone against bone
Compact bone – made up of circular structures – the Haversian system
Cornell University
**Haversian system** – a unit of circular structures inside more circular structures that give compact
bones its strength
Spongy bone – is porous; provides support as a “shock absorber”
Periosteum – outer covering; allows nutrients & thing to get into and out of bon
bone
Bone marrow - produces blood cells or stores fat
- red marrow – red blood cells
- yellow marrow – stores fat
Osteoblasts – bone forming cells
- at birth – you had ~300+ bones in your body
- eventually fused & ended up with 206 bones
Osteoclasts – bone cells that break down other bone tissues (older) & releases Ca
& P into bloodstream
Ligament – tough, band-like
like substance that connects bones at joints
Joint – where 2 or more bones meet
Moveable joints – allows for a wide range of movement
- pivot – ex. Neck
- ball & socket – ex. Shoulder, hip
- hinge – ex. Knee, fingers
- gliding – ex. Vertebrae, ankle
Immovable joints – allows little or no movement
- ex. Skull, pelvis
Section: Muscular System
Key Words: muscle,, cardiac muscle, contract, involuntary muscle, muscular system,, smooth muscle, skeletal muscle,
skeletal system, voluntary muscle
Essential Questions:
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Identify functions of the muscular system
Know that there are three types of muscles: skeletal, smoot
smooth, and cardiac
Understand how each type of muscle functions within our bodies
Perform simple activities that use all three types of muscles
Begin to identify ways that body systems interact with each other
Muscle – an organ that can relax and contract to allow movement
- approximately 600+ muscles in the body
o Strapedius – smallest muscle – inside the ear
o Sartorius – longest muscle – from hip to knee
- over 30 muscles in the face
2 types
o Voluntary
§ Muscles you are able to control
• Legs, arms, face, etc.
o Involuntary
§ Muscles you cannot consciously control
• Blood through vessels and heart
• Food through digestive tract
Levers – your body uses the skeleton and muscles as levers
- makes life easier
- simple machines – one movement
- lever is a bar that moves at a fixed point – fulcrum
- 3 types:
o 1st class
§ E
F
L
(effort/fulcrum/load)
§ Fulcrum in the middle
§ Ex. Skull up/down
• Vertebrae is fulcrum
nd
o 2 class
§ F
L
E
(fulcrum/load/effort)
§ Fulcrum is at one end and effort at the other
§ Ex. Standing on ball of foot
• Calf muscle is effort – body is load – ball is fulcrum
rd
o 3 class
§ F
E
L
(fulcrum/effort/load)
§ Fulcrum is at the end and effort is in the middle
§ Ex. Leg when you move
• Fulcrum is your hip – effort is thigh muscles and knee is load
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Muscle tissue – skeletal, smooth, cardiac
Skeletal
Smooth
Cardiac
- muscles that move bones
- non-striated
- found only in heart
- attached by tendons
- move internal organs ex.
- striated
Intestines, bladder, blood
- most abundant
- contracts
vessels,
etc.
- look striated (striped)
- approx. 70 per min
- contract and relax slowly
- voluntary
- contract quickly
- tire easily
Muscles at work
- work in pairs
- 1 contracts and other relaxes
- Always pull, never push
- Uses energy – chemical energy (ATP)
o Glucose – sugar – has bonds
§ When bonds break, chemical energy changes into mechanical energy
§ Allows you to contract muscles
§ If supply of glucose is used up, muscles tire
- the more muscle used, the larger they get
- not used, become smaller
- muscles use protein – myoglobin (carries O2)
Skin
Skin – largest organ in the body – largest sense organ
- 2 layers
o Epidermis
§ Top, new cells constantly produced
§ Produces melanin
• Melanin- pigment that gives skin color
• The more you have, the darker the skin tone
• Increases with exposure to UV Light
o Dermis
§ Layer under epidermis
§ A lot thicker
§ Contains blood vessels, nerves, oil & sweat glands
§ Fat cells are found here to help insulate body
§ Extra fat is stored here
- Functions
o Protection (most important!)
o Sensory response
o Formation of vitamin d
o Regulation of body temp
o Excretion of wastes
• protection
o 1st defense
o Helps prevent physical or chemical injury and disease
o Glands secrete fluids to fight off & destroy bacteria
o Prevents excess water loss
• Sensory
o Has specialized nerve cells
o Can detect temp, pressure & pain
• forming vitamin d
o absorbs Ca from food we eat
o uses uv light in skin to produce this vitamin
• heat & waste exchange
o regulates body temp
o blood vessels in skin hold or release heat
o blood vessels expand/dilate – more blood flow – more heat
o constricted gives reverse effect
o contains 3 million sweat glands
o dilated blood vessels cause them to open also release water, salt &
urea
- injuries
o large coverage of injuries like burning or rubbing away from epidermis
o leaves no cells left to divide to repair
o water loss is great
o nerve damage can result
o infection can lead to more damage or death