Fundamentals of Biology: Lecture Outlines - Chapter 37: Protection, Support, Movement
Integumentary System
EPIDERMIS
- outer layer
- stratified squamous epithelium
- Keratinocytes - produce keratin
- Melanocytes - produce brownish pigment
DERMIS
- dense connective tissue
- elastin + collagen fibers
Sweat Glands
Oil Glands
Hair
- mostly keratinized cells
"permed" hair - disulfide bridges broken and reformed
Skin as an endocrine gland:
Vitamin D
- produces
- helps body absorb calcium
Trouble with Tanning
Sunburn
- pale skin burns after 14 minutes
Botox-botulinum toxin
SKELETAL SYSTEM: BONES
FUNCTIONS:
- movement
- support
- protection
- mineral storage
- blood cell formation
Bone Structure
Spongy bone
Compact bone
Cells
- Osteocyte
- Osteoblast
- Osteoclast
Bone Formation:
- cartilage model
- blood vessel invades
- osteoblasts
- marrow cavity
- secondary bone-forming centers
- blood vessels and nerves
Bone Remodelling
- mineral constantly being deposited
- in response to sress
Osteoporosis - brittle bones
Causes:
- decreased activity
- lack of physical
- loss of
- too much
- low sex hormone
MUSCULAR SYSTEM:
Skeletal muscle
- striated
- arranged in bundles
- muscle cell =
- act at
- Antagonistic pairs
agonist (prime mover)
antagonist
Tendons - dense regular connective tissue
- tendinitis
Bursae - fluid-filled sacs
- bursitis
Muscle Structure and Function:
3 connective tissue coverings
- basic unit of contraction =
- made up of thin (actin) and thick (myosin) filaments
Z band
A band
H zone
I band
Sliding Filament Model of Muscle Contraction:
Z bands move closer together by sliding of actin filaments past myosin
1. Cross bridges form
2. Cross-bridges are activated
3. Power stroke
4. Cross-bridges are broken
5. Repeat
Rigor motis -
Energy (ATP) for Contraction:
1. Creatine phosphate
2. Aerobic cellular respiration
3. Lactate fermentation
Control of Contraction:
Motor neurons inhibit or stimulate
- action potential spreads along axon
- signals spread into muscle through special extensions of plasma membrane
- Calcium ions stored in sarcoplasmic reticulum
- Action potential triggers release
- Calcium allows cross-bridge formation
But how?
- in resting muscle
- proteins (troponins and tropomyosins) block
- calcium binds to troponin
- causes it to change shape
- myosin head can bind
Muscle Tension
- cross-bridge formation
- Isometric
- Isotonic
Motor Units
- motor neuron and
- size of motor unit related to amount of fine control
- in eye
- in leg
Muscle Twitch - muscle cell contracts and relaxes
Tetanus
- repeated stimulation
Review of Chapter 37 - p. 662-663
Review questions 1, 3c, 4, 5, 7, 8
Self quiz 1-7
Critical thinking #3