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Regulation and
Homeostasis in the
Human Body:
Overview
How do Humans and other complex mammals
maintain homeostasis? They must carry out all
needed life functions in a coordinated way.
What does our species need to accomplish?
Growth
Repair of injuries
Get energy
Get building materials
Get rid of waste
Keep away disease
Respond to changing environment
Reproduce
Eleven Body Systems work together to
maintain homeostasis and carry out these
tasks:
1. Nervous System
2. Endocrine System
3. Lymphatic System 4. Circulatory System
5. Respiratory System 6. Digestive System
7. Excretory System 8. Skeletal System
9. Muscular System 10. Integumentary System
11. Reproductive System
1. Nervous System:
Structures: Brain, Spinal
Cord, Peripheral Nerves,
Neurons (Cells of nervous
system)
Functions: Coordinates
the body’s response to
changes to internal and
external environment
2. Endocrine System – Hormone System
Structures: Glands Hypothalmus, pituitary, thyroid,
parathyroids, adrenals,
pancreas, ovaries (in females),
testes (in males)
Functions: Produce Hormones.
Controls growth, development,
metabolism, and reproduction
3. Lymphatic System – Immune System
Structures: White blood
cells, thymus, spleen,
lymph nodes, lymph
vessels
Function: Helps protect
the body from disease;
collects fluid lost from
blood vessels; returns the
fluid to the circulatory
system
4. Circulatory System
Structures: Heart,
Blood vessels, blood
Functions: Brings
oxygen, nutrients, and
hormones to cells;
fights infection;
regulates body
temperature
5. Respiratory System
Structures: Nose,
pharynx, larynx, trachea,
bronchi, bronchioles, lungs
Functions: Provides
oxygen needed for cellular
respiration and removes
carbon dioxide from body
6. Digestive System
Structures: Mouth,
pharynx, larynx,
esophagus, stomach,
liver, pancreas, small
and large intestines,
Function: Breaks down
foods into simple
molecules that can be
used by the body for
respiration and building
cells
7. Excretory System
Structures: Skin, lungs,
kidneys (nephrons),
ureters, urinary bladder,
urethra
Functions: Removes
waste products of
metabolism from the
body
8. Skeletal System
Structures: Bones,
cartilage, ligaments,
tendons
Functions: Supports the
body; protects internal
organs; allows movement;
stores mineral reserves;
provides a site for blood
formation
9. Muscular System
Structures: Skeletal
muscle, smooth muscle,
cardiac muscle
Function: Works with
skeletal system to produce
voluntary movement; helps
circulate blood and move
food through the digestive
system
10. Integumentary System (Skin)
Structures: Skin, Hair, Nails, Sweat
and Oil Glands
Functions: Serves as a barrier against
infection and injury; Helps to regulate
temperature; Protects against UV light
11. Reproductive System
Structures:
Female- Uterus, Fallopian
tubes, ovary, cervical canal,
cervix, vagina
Male – Penis, Vas Deferens,
Prostate, Epididymis, Testes,
Scrotal Sac, Seminal Vesicle
Function: Produces
reproductive cells; in females
nurtures and protects
developing embryo
Support and Motion
Functions of the SKELETAL AND
MUSCULAR SYSTEM
How does the human body
move from place to place and
have the ability to run, blink
or build things?
These things are all made
possible by the skeletal and
muscular systems.
A. Skeletal
Skull
System
There are 206
bones in the adult
human body.
These bones
provide a system
of supports and
levers on which
muscles can
produce
movement
Sternum
Ribs
Vertebral
column
Clavicle
Scapula
Humerus
Radius
Pelvis
Ulna
Carpals
Metacarpals
Phalanges
Femur
Patella
Fibula
Tibia
Tarsals
Metatarsals
Phalanges
Bones are a solid
network
ofStructure
living cells
and
Figure
36-3 The
of Bone
protein fibers that are surrounded by calcium
deposits. Bones contain blood vessels and cavities
containing marrow. Red marrow produces red
blood cells, white blood cells and platelets
Bone
Marrow
Joints are placesFigure
where
one
bone
attaches
to and
another.
36-4
Freely
Movable
Joints
Their
Movements
Each Section
type36-1
of joint is designed to allow movement
without damaging the other bones. Joints in the skull
allow no movement, joints in the spine allow a small
amount of movement and those shown below allow
movement in one or more directions.
Clavicle Joint
Ball-and-Socket
Pivot Joint
Elbow
Hinge
Knee Joint
Saddle Joint
Section 36-1
Knee
Joint
Ligaments are a
tough connective
tissue that attach
bones to bones
Tendons are
connective tissue
which attach bones
and muscles to
allow bones to move
Muscle
Tendon
Femur
Patella
Bursa
Ligament
Cartilage
Fat
Fibula
Tibia
B. The Muscular System
More than 40% of the average human is muscle.
Muscles are involved in both voluntary actions and
involuntary actions. Three types of muscles cells are:
•Skeletal – Attached to bones for voluntary actions and
controlled by the central nervous system
•Smooth – Found in the digestive tract and the blood
vessels to move food and blood. Control involuntary
actions (you do not decide for them to work)
•Cardiac – Heart muscle cells are involuntary.
Figure 36-7 Skeletal Muscle Structure
Skeletal
muscles are made up of clusters of filaments
Section 36-2
of proteins known as actin and myosin which
control muscle contraction and relaxation
Nervous system cells known as motor neurons
are attached to skeletal muscle cells to control
the voluntary movement.
Threadlike Nerve
or neuron
Axon or junction
Figure 36-8 Muscle Contraction
During Muscle
contraction Actin
filaments slide over
myosin filaments
shrinking the
muscle
Energy for muscle contraction is supplied by
ATP
Figure 36-11 Opposing Muscle Pairs
Skeletal
Section 36-2muscles work in opposing pairs.
When one muscle contracts, the other relaxes.
Movement
Movement
Triceps
(contracted)
Biceps
(relaxed)
Biceps
(contracted)
Triceps
(relaxed)
Nutrition and Waste Removal
How does the human body take in required
nutrients and get rid of wastes?
The Digestive and Excretory Systems are
responsible for bringing in food and getting rid of
the leftovers.
Overview of Nutrients
Food supplies the raw materials for
building molecules your body needs, such
as:
• enzymes
• Lipids in cell membranes
• DNA
Food contains 45 substances your
body needs but cannot manufacture.
The nutrients your body needs are water,
carbohydrates, fats, proteins, vitamins and
minerals.
WATER – Most of the bodies reactions take place in
water. Humans need an average of 1 liter of water a
day. Dehydration causes many problems throughout
the body.
CARBOHYDRATES – Sugars and starches are used by the
body to provide the simple sugars needed for Respiration
(energy)
FATS- Deposits of fats protect body organs, insulate
the body and store energy, make up cell membranes and
coat the nervous system cells
PROTEINS – Supply the raw materials for
growth and repair in the form of enzymes
VITAMINS – Organic molecules that work with
enzymes to control body processes.
MINERALS – Inorganic nutrients that are
needed in small amounts. Calcium is needed to
build bones, Iron is needed for red blood cells.
Food Guide Pyramid
A Balanced Diet
Fats
Sugars
C. The Digestive System
Mouth
Pharynx
Salivary
Glands
Esophagus
Liver
Gallbladder
Stomach
Pancreas behind stomach
Large Intestine
Small Intestine
Rectum
The Process of Digestion: The path of food
Each organ of the digestive system helps convert foods
into simpler molecules that can be absorbed and used
by the cells of the body.
Teeth – Cut, Crush and tear food
Salivary glands – Moisten food to make it easier to chew and
pass through the system, enzymes break down starches
Esophagus – Tube from mouth to stomach connected by
Pharynx. Works by contraction of the smooth muscles known
as peristalsis.
Stomach – Muscular sac that churns and mixes food with acid
As food leaves the stomach it travels into the small
intestine
the doudenum, and it mixes with
Sectionthrough
38-2
with enzymes and digestive fluids from the liver,
gallbladder and pancreas.
Liver
Gallbladder
Doudenum
Bile Duct
Pancreas
Chemicals from the pancreas breakdown
.
carbohydrates, proteins, lipids and nucleic
acids. In addition chemicals from the pancreas
produce substances which neutralize stomach
acid.
If the acid travels too far without being
neutralized it will change the shape of
enzymes and cause problems in the
body.
The Liver makes bile which acts like a
detergent to break down fat. The gall
bladder is a storage area for the bile
The small intestine absorbs nutrients from the
digestive
systems and transfers many of the nutrients
Section 38-2
to the circulatory system. The small intestine is lined
with small fingerlike projections known as villi which
designed to have a large surface area for this task.
Small
Intestine
Villus
Large intestine (Colon)
Food that enters the large intestine is nutrient-free.
Usable nutrients have been absorbed leaving water and
undigestible substances. The large intestine removes
water from the waste. Once water is eliminated the
solid waste passes out of the body through the rectum.
The appendix is located just below the entry to
the large intestine. In many animals it helps
digest difficult materials such as cellulose. In
humans the appendix is not used for any purpose
in digestion. When it gets infected it is
removed.
D. Excretory System:
In the process of obtaining nutrients and
carrying out chemical reactions the human
body produces wastes (CO2, Urea, Salts). If
some of these wastes are not removed they
could threaten homeostasis. Excess chemicals
that are not toxic also need to be removed.
The skin, lungs and kidneys all function to
get rid of excess or harmful products
produced in the body.
Kidneys contain millions of small filters called
Section 38-3
nephrons
, which filter your entire blood supply
every 45 minutes. Filtration takes place because
blood pressure forces water, salt, glucose, amino acids
and urea into structures known as Bowman’s capsules.
(Protein and Blood are too large to enter)
Kidney
Nephron
Bowman’s
Capsule
Processes of osmosis and active transport filter the
useful materials from the waste (urine). Substances
your body needs to keep are returned to the blood
stream. Substances your body needs to get rid of are
passed from the renal tubes to the urinary bladder.
Vein
Kidney
Ureter
Urinary Bladder
Urethra
Artery