skeletal, muscular & integumentary systems chapter...
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SKELETAL, MUSCULAR & INTEGUMENTARY SYSTEMS
CHAPTER 36 Biology
36-1 SKELETAL SYSTEM
FUNCTIONS:
bones provide rigid framework against which muscles can pull
give shape and structure to the body
support & protect internal organs
HUMAN SKELETON
•AXIAL SKELETON = skull, ribs, spine & sternum
•APPENDICULAR SKELETON = arms, legs, shoulder & pelvis
Bone Structure
solid network of living cells and protein
fibers that are surrounded by deposits of
calcium salts
Figure 6.3
Periosteum – tough membrane covering bone’s surface
Compact bone – hard material composed of cylinders underneath periosteum; enables bone to endure large amount of stress upon impact
Haversian Canal– central channel within cylinders containing blood vessels and nerves; carries nourishment to living bone tissue
Osteocytes – mature bone cells
Spongy Bone – network of connective tissue inside compact bone
Bone Marrow – soft tissue inside bones; red produces rbc’s and some wbc’s; yellow consists mostly of fat cells for energy reserve
Structure of Bone
Figure 6.6a, b
Bone Development
CARTILAGE: tissue that makes up
most of an embryo’s skeleton
OSSIFICATION: – process in which
cartilage is replaced with bone
Begins in embryos 7 mo’s before
birth
Bone growth until early adulthood
Bone thickness, remodeling, and
repair
•Bone cells replace cartilage in long bones of limbs
•Bones stop elongating when cartilage is replaced at plates
Hyaline
cartilage Spongy
bone
Blood
vessel
blood
vessel
Epiphyseal
plate
cartilage
Spongy
bone
Articular
cartilage
Bone Elongation
Figure 6.8
1. IMMOVABLE JOINTS: prevent
movement (ex) skull joints
2. SLIGHTLY MOVABLE JOINTS:
permit limited movement (ex)
vertebral column, ribs
3. FREELY MOVEABLE JOINTS –
permit movement in 1 or more
directions
JOINTS – where 2 bones meet
FREELY MOVABLE JOINTS
1. HINGE: elbows, knuckles, toes
2. BALL-AND-SOCKET: shoulders, hip
3. SADDLE: base of thumb
4. PIVOT: elbow, top of spine
JOINT STRUCTURE:
LIGAMENTS, SYNOVIAL FLUID, BURSA
Figure 8.3a, b
36.2
MUSCLE FUNCTION: movement, provides force that pushes substances (blood & food) through body
•Muscle Fibers: elongated muscle cells making up tissue
MUSCLE TISSUE Voluntary Muscle: contractions consciously
controlled (ex) skeletal
Involuntary Muscle: movements not consciously
controlled (ex) smooth & cardiac
SKELETAL SMOOTH CARDIAC
Skeletal Muscle
Figure 9.2 (a)
TENDON: tough
connective tissue
that connects
muscle to bone
MUSCLE STRUCTURE
MYOFIBRILS: muscle
fibers within a cell
SARCOMERE: unit of
myofibril
PROTEIN FILAMENTS:
ACTIN – thin
MYOSIN – thick
STRIATED MUSCLE:
striped due to
alternating light and
dark bands
Myofilaments: Banding Pattern
Figure 9.3 (c, d)
MUSCLE CONTRACTION: sliding-filament model
Thick myosin = purple
Thin actin = orange
(a) Partial overlapping
sarcomere is long
(b) Filaments slide past
each other
shortens sarcomere
(c) Totally overlapped,
Z lines closer
together
Neuromuscular
Junction
CONTROL OF MUSCLE CONTRACTION:
NEUROMUSCULAR JUNCTION: point of
contact between neuron and skeletal muscle cell
ACETYLCHOLINE: chemical released that
sends impulse to muscle fiber calcium
released muscles contract
36-3 The Integumentary System
Skin
Nails
Hair
Sweat & Oil glands
FUNCTIONS:
BARRIER AGAINST INFECTION & INJURY
REGULATE TEMP
REMOVES WASTE FROM BODY
PROTECTION AGAINST UV RADIATION
SKIN •EPIDERMIS: outer layer of skin
•Keratin - tough fibrous protein
•Melanin – dark brown pigment
•DERMIS: inner layer; has bv’s collagen, nerve endings, sensory receptors, hair follicles, glands
CROSS SECTION OF SKIN
FUNCTIONS:
•protects scalp form UV,
•provides insulation from cold
•hairs in nostrils, ears, and eyelashes prevent dirt from entering body
HAIR FOLLICLE: cluster of cells that produces hair
SEBACIOUS (OIL) GLANDS: secrete oily substance that helps maintain hair condition
HAIR
HAIR SHAFT EMERGING
FROM A FOLLICLE
KERATIN:
protein
that makes
up hair
MELANIN:
pigment
producing
hair color
NAILS •KERATIN: makes up nail
• FUNCTION: protects ends of fingers and toes
•NAIL ROOT: area of rapidly dividing cells
•CHANGES IN SHAPE, STRUCTURE & APPEARANCE MAY BE AN INDICATOR OF DISEASE