Chapter 36
The Integumentary, Skeletal, &
Muscular System
John Hizny
Lexi Coolbaugh
Sarah Schultz
James Avery
Adam Werner
Section 36-1
Skin
Largest organ in the body
Part of integumentary system
Integumentary includes skin, hair, nails, and
number of important glands in skin.
 Skin has three layers

1. Outer layer - Epidermis
2. Inner Layer -Dermis
3. Lowest Layer - Hypodermis
Supports the Epidermis
 Contains important cells for:
Nerve endings
Blood Vessels
Smooth Muscle
 The body’s Sweat/Oil Glands are
located here also

Produces cells that are pushed toward
the surface. Produces keratin as they
move upward.
 Keratin – Tough, flexible protein

◦ Major protein found in fingernails
◦ Forms a tough waterproof layer on top of
skin
•Hair is produced from columns of cells that
are filled with keratin and then…. DIE.
•Clusters of cells make up Hair Follicles.
•Toenails/fingernails are formed by keratinforming cells for a flattened plate.
Section 36-2
Bones

All vertebrates have an internal skeletal
system
 Bones store supplies of calcium and
phosphorous

Internal Skeletal System
◦ Provides support for the upper body
◦ Attachment sites for muscles
◦ Protects internal organs
Bone Structure
Periosteum- tough layer surrounding
bones
 Inside the periosteum is a dense layer of
compact bone.
 Spongy bone is found inside the compact
bone.
 Osteocytes- Cells found in C & S bone.

◦ Help build and maintain bones
Bone Growth

Bones are produced by Cartilage.

Cartilage is produced at growth plates &
gradually is replaced by bone as the
skeleton enlarges.
Joints
A place where two bones meet.
 3 kinds of joints:

◦ Fixed
 Little or no movement between bones
 Mostly located in the skull
◦ Slightly Moveable
 Small amount of movement
 Mostly located in a Spinal Column or Ribs
◦ Freely Moveable
 Wide Range of movement
 Ex: Shoulders and hips
Joints Continued
Joints are enclosed by a Joint Capsule.
 Inside the capsule is Synovial Fluid

◦ Natural lubricant that reduces friction &
allows the cartilage coated bones slip past
each other easily
Section 36-3
Muscle Tissue

There are 3 types of muscle tissue:
◦ Skeletal
◦ Cardiac
◦ Smooth

Each of these three types muscle, have a
different cellular structure.
Skeletal Muscle Tissue
Generally attached to the bones of the
skeleton and is usually under voluntary
control.
 Skeletal muscle tissue is behind every
conscious movement you make

◦ Ex: Lifting a weight
 This is because most skeletal muscle tissue is
controlled directly by the nervous system.
Cardiac Muscle Tissue
Cardiac muscle tissue is found in just one
place : The Heart
 Cardiac muscle tissue is striated, but the
smaller Cardiac muscle cell have just one
nucleus, and they are not under the direct
control of the Central Nervous
System

Smooth Muscle Tissue
Smooth muscle tissue is found in the walls
of many internal organs, except the heart.
 The cells of the smooth muscle tissue are
spindle shaped, have a single nucleus, and
are not striated.
 Not always under the conscious control
of the nervous system.
 Responsible for actions not under
voluntary control.

Muscle Structure
Myosin- Thick filaments that are made of
protein.
 Actin- Thin filaments that are made up of
another protein.

Sliding Filament Theory

When hundreds of thousands of actinmyosin cross-bridges go through their
cycle in a fraction of a second, the muscle
cell contracts with siderable force.
Muscle Contraction


To make well-coordinated movement,
muscle contractions must be carefully
controlled.
A single motor neuron may form synapse to
one or several muscle cells. An impulse in
the motor neuron causes the release of a
neurotransmitter acetylcholine.
◦ This causes a new action potential. In turn causes
the release of calcium ions into the cytoplasm of
muscle cells.
 When calcium flows into the cytoplasm, cross-bridges
form, and the muscle contracts.
Muscles and Movements
Muscles produce force by contracting.
 Attached to bones by tendons, a muscle
can pull two bones together, using the
joint between them as a lever.
 An individual muscle can pull by
contracting, but cannot push.

◦ If that’s true, then how can you push a door
open or do a pushup?
 The answer is that skeletal muscles are arranged in
pairs. These pairs oppose each other and produce
forceful movements in either direction.
Section 36-4
Specialized Skeletal Muscle Fibers

Skeletal muscles contain two main types
of muscle fibers
◦ Red
◦ White
 Whose properties make them specialists at
different kids of exercise.
Red Muscle Fibers
Contain large amounts of reddish oxygenstoring protein myoglobin.
 Red fibers have rich blood supplies and
plenty of mitochondria to produce ATP.

White Muscle Fibers
Called fast- twitch muscle fibers and can
generate powerful contractions.
 The contain few mitochondria , these
fibers contain greater densities of
contractile proteins than red fibers do.

◦ The powerful fibers fatigue easily, however,
which means that they can produce maximum
contractions for only a few seconds at a time.
Exercise Muscle Cells

Aerobic exercises, such as running,
swimming, and bicycling cause your body
system to become more efficient.
◦ Resistance exercise, such as weight lifting,
increase muscle size.