Download Ch 37 – Introduction to Body Structure

Ch 37 – Introduction to
Body Structure
Outline
1.
2.
3.
4.
Body organization
Skeletal system
Muscular system
Skin, hair and nails
37.1 Levels of structural organization
Cells are grouped into 4 types of body tissues:

EPITHELIAL TISSUE - Cover or line body surfaces; some are capable of
producing secretions with specific functions.


CONNECTIVE TISSUE - Connects and supports parts of the body; some
transport or store materials.


Ex. Blood, Bone, and Adipose Tissue (Fat)
MUSCLE TISSUE - Specialized for CONTRACTION, which brings about
movement.


Ex. outer layer of skin
Ex. Skeleton Muscles &Heart
NERVE TISSUE - Specialized to generate and transmit electrochemical
Impulses that regulate body functions.

Ex. Brain and Optic Nerves
Body Tissues
Stem cells

Stem Cells- Any embryonic stem cell is
capable of becoming any type of tissue
found in the adult body

Read section in book.
Cell Differentiation Video
Stem cell research
Know
general
system
function –
p. 848 in
Book!
Body cavities

House and protect the major internal organs.

Organs are suspended in a fluid that supports
their weight and prevents them from being
deformed by body movements.

CRANIAL CAVITY - encases the
brain.

SPINAL CAVITY - extending from
the cranial cavity to the base of
the spine, surrounds the Spinal
Cord.

THORACIC CAVITY - The upper
compartment, contains the heart,
the esophagus, and the organs of
the respiratory system - the lungs,
trachea, and bronchi.
Separated
by
diaphragm

ABDOMINAL CAVITY - The
lower compartment, contains
organs of the digestive,
reproductive, and excretory systems.
Endothermy

Like all mammals, humans are endotherms.

Humans maintain a fairly constant body temperature of
98.6ºF.

Very high temperatures, such as those during a fever,
can be dangerous b/c they can inactivate critical
enzymes.

To release heat, blood flow is increased to blood
vessels just under the skin.

To retain heat, blood is shunted away from the skin.
37.2 Muscle and Bones
37.2 Skeletal system

Your skeleton is made mostly of bone – a type of
hard connective tissue, that is constantly being
formed and replaced.

206 bones

Axial skeleton – skull, spine, ribs and sternum
(forms axis)

Appendicular –forms appendages or limbs;
arms, legs, pelvis, shoulder (comes off of axial)
Axial & Appendicular
Do NOT need
to know all
bones for the
scope of this
class
Bone
Bone layers

Periosteum – tough
exterior membrane –
contains many blood
vessels that supply
nutrients to the bone

Compact bone – outer
layer of bone – compact

Spongy bone – loosely
structured network of
connective tissue
Bone Marrow

Bone marrow – soft tissue

Red bone marrow – begins production of all
blood cells and platelets

Yellow bone marrow – mostly fat, stores
energy
Bone growth

In early development the skeleton is mostly
cartilage, a type of connective tissue that serves
as a template for bone formation.

During development, most cartilage is gradually
replaced by bone as minerals are deposited.

Deposits of calcium and other minerals harden
bones, enabling them to withstand stress.
Bone growth

In compact bone, new cells are added in layers
around narrow, hollow channels called Haversian
canals.

Osteocytes – bone cells become embedded in
the tissue


Build bone
Bones continue to thicken and elongate through
adolescence as bone cells replace cartilage.
Cartilage degenerates as new bone cells are
added, causing bones to lengthen.

Look for open bone plates
Bone growth
Osteoporosis

Bone loss – porous bone – brittle bones

Bones respond to stress = exercise

B/c women’s bones are smaller, cannot afford to
lose as much tissue as men.

Decrease in sex hormones after menopause has
also been linked to decrease in bone production

Dowager’s hump - lose out of vertebrae

Prevention- exercise, nutrition, calcium
supplements


Weight-bearing and resistance exercise
Nutrition – calcium, leafy green veggies, whole grains,
legumes
Body joints



JOINT – where two bones meet
Bones held together by ligaments (bone to bone)
 Stretch only so far
 Stabilize
 Prevent range of motion
 Ligament injury - SPRAIN
Different types of joints for different fcn
 Immovable – little or no movement – skull
 Slightly movable – limited – vertebrae
 Freely movable –shoulder, hip etc
Table 2 - Movable joints
know – p. 854 book!
Joint
Type of
movement
Ball and socket All types
Pivot Joint
Rotation
Hinge Joint
Bending &
straightening
Sliding motion
Gliding joint
Saddle joint
Examples
Shoulders and
hips
Top of spine
(turning of head)
Elbows, knuckles
of fingers & toes
Wrists and ankles
Rotation, bending, Base of thumbs
& straightening
37. 3 Muscle Tissue
3 types: in book p. 847
1.
Skeletal muscle – voluntary muscle b/c you can
consciously control its contractions. Moves bones in
the trunk and limbs.
2.
Smooth muscle – involuntary b/c you cannot
consciously control its slow, long lasting contractions.
3.
Cardiac muscle – involuntary and found in the heart
Muscles are attached to bones by tendons.
 Muscle pairs move parts of the body by pulling
on bones

Flexor – causes joint to bend
 Extensor – causes joint to straighten

Tendon injury

Strain (tendons strain; ligament sprain)

Tendonitis – inflammation of a tendon
Muscle structure

Sarcomeres shorten
during muscular
contraction

During muscle
contraction, actin &
myosin interact.


A and M are protein
filaments
Energy is needed for
muscles to contract.

Before a muscle is
stimulated is relaxed

Stimulated by a signal
molecule form a nerve
cell – cause actin &
myosin to slide and
overlap

Sarcomere is contracted
when myosin and actin
completely overlap each
other.
Rigor mortis – after death, ATP production stops. Without ATP,
myosin heads attach to actin filaments, but cannot detach. As a
result, muscles are locked into position, making the body rigid. This
condition lasts up to 25 hours after death.
37.4 Skin, hair, nails

Skin makes up about 15% of your body
weight – is the largest organ of the body!

Skin, hair, nails make up the integumentary
system
Layers of the skin
SKIN

EPIDERMIS - Outermost layer – about as thick as the
page of your book – made of several layers of epithelial
cells

DERMIS – innermost layer


contains BLOOD VESSELS, NERVE ENDINGS, GLANDS (OIL
& SWEAT), SENSE ORGANS, SMOOTH MUSCLES, AND
HAIR FOLLICLES.
SUBCUTANEOUS TISSUE - Layer of connective tissue
which is mostly fat


Anchors skin to underlying organs
Acts a shock absorber, provides additional insulation to help
conserve body heat, and stores energy.
Skin Cancer

Can result from genetic
mutations caused by
overexposure to UV
radiation.

Most common type of skin
cancer are carcinomas
which originate in skin
cells that do not produce
pigments.

Malignant melanomas
grow quickly and spread
to other parts of the body.
Basal cell carcinoma
ABCD’s of Recognizing Melanomas