Unit 19 – Skin, Muscle and Bone

The bulk of the mammalian body is made of muscle and bone and this chapter examines the muscular and skeletal systems as well as the integumentary system that covers and contains them.

Integumentary System- aka the skin

** the skin is the largest organ

Uses of the skin-

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Structure of the skin

Acne- defn:

Sensory Nerve Endings for the dermis

Ruffinis Organ
Free Nerve Ending
Meissners Corpuscle
Merkels Discs
Pacnian Corpuscle

Skeletal Systems-

Skeletal systems vary with organisms but all give the body shape and support and most allow for locomotion

1.  hydrostatic skeleton-

ex: Hydra and earthworms

in the worm liquid is squeezed into chambers to extend forward and them the rest of the body pull up to them to move along

2. exoskeletons

Ex: typical of arthropods

Ecdysis-

3.  Endoskeletons-

Typical of the

The Human Skeleton-

Composed of two main sections

1.  axial skeleton-

functions:

2.  appendicular skeleton-

functions:

The Axial Skeleton-

Parts-

1. Skull-

includes :

Cranium-

maxilla –

mandible-

2. Vertebral Column-

Appendicular Skeleton- two sections

1.  pectoral skeleton-

2.  pelvic skeleton-

Pectoral Skeleton-

Pectoral girdle-

Pelvic Skeleton-

Pelvic Girdle-

Relationship of cartilage to Bone

Bones form in two ways

1.  intramembranous bone-

2.  endochondral bone-

Typical bone morphology

Bones Meet at joints

Muscles

Skeletal muscles are responsible for all movement in the body

*

Structure of Muscle

The Sarcomere

The sarcomere is made of thin filaments of ______and thick filaments of ______

______ has “heads” that are movable when activated with ATP

The lettered lines refer to traditional names for the fiber parts from the days of early microscopy

Contraction of muscle

All or None Response-

** once a muscle contracts it needs another muscle to pull it back to its original position

Antagonists-

Synergists-

Patterns of Muscle Contraction

Terms-

Single twitch-

Summation of response-

Muscle Tone-

Tetany-

Fatigue-

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