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THE HUMAN
BODY
Bellwork 11/8
Why does our body sweat
when we are hot or shiver
when we are cold?
Maintaining Homeostasis

Shivering occurs when your muscles rapidly
contract and relax.

Sweating helps to cool your body. Your
internal body temperature will be close to 37
degrees C. If you become sick, you body
temperature may rise but it will return to 37
degrees C when you are well again.

This action produces heat that helps keep
you warm.
Homeostasis
 The
maintenance of a stable
internal environment in the
body in spite of changes in the
external environment
 Constantly working to keep the
body in balance
 Outside factors make this hard
Stress and Homestasis

Stress- The
reaction of
your body to
potentially
threatening,
challenging, or
disturbing
events







Your heart may beat more rapidly
Your breathing may increase
Your endocrine system might release a
chemical called adrenaline into your
bloodstream
Adrenaline gives your body burst of energy
and prepares your body to take action
Your muscles work harder and require more
oxygen
Oxygen is carried to the circulatory system
Your heart then beats faster so that more
oxygen can get into your body.
Body Organization
 Cells
 Tissues
 Organs
 Systems
Cells
 Building
blocks of life
 Body is composed of billions of
different cells
 When cells of the same type
work together to do a job they
form a TISSUE
Tissues
Tissues
 Four
main types
Epithelial
 Nervous
 Muscle
 Connective

Epithelial Tissues
 Cover
and protect underlying
tissue
 Skin for example
Nervous Tissue
 Send
messages through the
body
 Found in

Brain, nerves, and sensory
organs
Muscle Tissue
 Made
of cells that contract and
relax
 Produce movement
Connective Tissue
 Many
jobs
Joins/supports/insulates
 Keeps organs from falling apart
 Examples


Bone and blood
Organs
 Two
or more tissues working
together form an ORGAN

Stomach uses all four types of
tissues to perform digestion
Body Systems
 Organs
working together form
systems
 12 major systems in the body
 Some organs are part of more
than one system at a time
The Skeletal System
Skeletal System
 Made
of bones, cartilage and
the connective tissue that
holds the bones together
 206 in adults
 Multiple Functions
Functions of Skeletal
System
 Protection
 Storage
 Movement
 Blood
Cell Formation
Protection
 Prevents
damage to organs
Skull protects brain
 Ribcage protects heart, lungs,
etc…
 Spine protects spinal cord

Storage
 Minerals
needed to help
nerves and muscles work
 Long bones can store fat for
energy
Movement
 Allow
for places
for muscles to
attach
 Movement of
skeletal muscles
allow to move
Blood Cell Formation
 Marrow
of
some
bones
make cells
of the blood
Bone Structure
 Made
of connective tissue and
minerals

Minerals deposited by cells
called osteoblasts
 Two

kinds of tissue
Compact bone and spongy bone
Bone Structure
 Compact

Bone
Rigid and dense
 Spongy
Bone
Many open spaces
 Provide strength and support of
bone

Bone Structure
 Bone
Marrow
Soft tissue inside bone
 Red marrow produces red and
white blood cells
 Yellow marrow stores fat

Bone Growth
 Bones
start as cartilage and
harden as you get older
 Tips of ears and nose the
cartilage never gets hard
Joints
 Place
where two or more bones
meet
 Two major types of joints
Immovable
 Movable

Immovable Joints
 Little
or no movement is
allowed
 Bones of skull are held
together this way
Immovable Joints
Movable Joints
 Held
together by connective
tissue called ligaments
 Three Main Types
Gliding Joint
 Ball-and-Socket Joint
 Hinge Joint

Movable Joints
 Cartilage
Protective covering over ends of
bones
 Keeps bones from rubbing
together

Gliding Joint
 Allow
bones to move past one
another

Found in hand and wrist
Ball-and-Socket Joint
 Allows
for movement in many
different directions
 Rotate at this joint
Shoulder
 Hip

Hinge Joint
 Open
 Knee
 Elbow
and close like a door
Muscular System
The Muscular System
 Made
up of all the muscles
that let you move
 Two Main Types
Involuntary
 Voluntary

Involuntary Muscles
 Muscles
that you do not have
to think about to control
 Act on their own
 Important for:

Breathing, heart beating,
blinking, etc…
Voluntary Muscles
 Muscles
that you control with
thought
 Movements

Smiling, speaking, raising your
hand, walking, etc…
Muscle Tissue
 Three
Types of Muscle Tissue
Smooth Muscle
 Skeletal Muscle
 Cardiac Muscle

Smooth Muscle Tissue
 Involuntary
Muscle
 Makes up the inside of many
organs
 Act without thought

Example: digestion in the
stomach is automatic
Smooth Muscle
Skeletal Muscle Tissue
 Voluntary
Muscles
 Attached to bones by tendons
 Responsible for moving
 Called striated muscles

Appear banded
 With
lots of use become tired
(fatigued)
Skeletal Muscle Tissue
Cardiac Muscle
 Found
only in heart
 Is involuntary like smooth
 Striated like skeletal

Unlike skeletal it never gets tired
Cardiac Muscle Tissue
Muscles at Work
 Function
by contracting
 Message from nervous system
 Work in pairs

When one muscle contracts its
mate relaxes to its original
length
Muscles at Work
Muscles at Work
Muscles at Work
Strength and Flexibility
 Some
muscles can be made
stronger and made to last
longer
Regular exercise can help
 Resistance and Aerobic
Exercise

Integumentary System
Integumentary System
 Made
up of skin, hair, and
nails
 Covers the body and helps
maintain homeostasis
 Skin is largest organ in body
Functions of Skin
 Protecting
the Body
 Maintaining Temperature
 Eliminating Wastes
 Gathering Information
 Producing Vitamin D
Protecting the Body
 Forms

a barrier
Keeps disease-causing
microorganisms out
 Keeps
important substances
inside body

Prevents you from drying out
Maintaining Temperature
 Blood
vessels in skin will
enlarge when you get hot

Allows more blood to area and a
temperature drop to occur
 Sweat
glands produce
perspiration
Eliminating Wastes
 Sweat
contains waste
materials
 Keeps some harmful materials
from building up in your body
 This is why sweat is salty
Gathering Information
 Lots
of nerve endings in skin
 As you touch things your body
collects information

Pressure/pain/temperature
 Keeps
you safe
Producing Vitamin D
 In
presence of sunlight
 Important for healthy bones
 Helps cells to absorb calcium
in food
 Only need a few minutes of
sunlight each day
Layers of the Skin
 Two
Main Layers

Epidermis

Dermis
Layers of the Skin
The Epidermis
 Outer
layer
 Thinner than dermis
 No nerves or blood vessels
 Cells of epidermis (epithelial)
are replaced about every 4
weeks
The Epidermis
 Outer

layer is dead cells
This is what protects and
cushions
 Shedding
of dead cells carries
away bacteria
 Melanin is produced in
epidermis
The Epidermis
 Melanin
protects skin by
creating a tan when exposed
to sun light
 Also cells in epidermis that
produce fingernails
The Dermis
 Inner
layer of skin
 Has:

Nerves/Blood Vessels/Sweat
Glands/Hairs/Oil Glands
 Sweat
and oil reach surface
through pores
The Dermis
 Hair

grow from follicles
Hair you see is made of dead
cells
 Oil
produced helps make hair
waterproof and keep skin
moist
Injuries, Disorders, and Diseases of
the Skeletal System
 Fractures
 Postural
Deformities
 Arthritis
 Cancer
 Osteoporosis
 Rickets
Fractures
A fracture is any break in the bone
 About 6 different types
 We will cover 3
 Simple
 Greenstick
 Compound

Simple Fractures
A
clean break of the bone
 Bone is often split into two
pieces
 No damage to skin
 May result in bruising
Simple Fracture
Greenstick Fracture
 Bone
is not completely broken
One side shows break
 Other just bends

 Most

commonly seen in children
Due to pliable nature of young
bones
Greenstick Fracture
Compound Fracture
 Also
known as an “Open” fracture
 Broken end of bone pushes out
and breaks through skin
 Can result in damage to tissues
and infection
Compound Fracture
Arthritis
Inflammation of one or more joints
 Causes range depending on type of
arthritis

Osteo arthritis is caused by wearing
away of cartilage
 Rheumatoid arthritis is caused when
body attacks and breaks down cartilage
(autoimmune disorder)

Rheumatoid Arthritis
Injuries, Diseases and
Disorders of the Muscular
System
 Sprains
 Strains
 Dystrophy
Sprains and Strains

A sprain is when a ligament gets
stretched too far


Symptoms of a sprain are: pain, swelling, and
bruising of the affected joint
A strain is an injury to a muscle or tendon,
usually occurring when stretched too far

Can lead to muscle tears when a rip occurs in
the muscle or tendon
Muscle Tear
Dystrophy
 Refers
to a group of diseases
 All result in a wasting of the
muscles
Loss of control
 May extend to internal organs


Leading to problems with organs
functioning or even death
Injuries, Disorders, Diseases of
Skin
 Hundreds
of different problems
can occur with the skin and
underlying connective tissue
 Will look at just two
 Acne
 Psoriasis
Acne
 Term
for pimples on the skin
 At puberty the oil glands of the
skin start producing an oily
material (sebum)

Sometimes the wall of the oil gland
breaks and spills the sebum within
the skin which causes redness,
swelling, and pus (a pimple)
Acne
Psoriasis
 Causes
are unknown
 Runs in families
 Results in areas of the skin
growing much faster than others

Creates red and scaly patches that
itch
Psoriasis
Can Happen On the Nails as Well