Body Systems
Anatomy – the study of the structure of an
organism and/or its parts
Physiology?
= the study of what
structures do.
Muscle contraction
Homeostasis –
the foundation of physiology
- maintenance of
a “steady state”
condition.
- the sum of all
processes is
called…
Why is
homeostasis
important?
Homeostasis – involves thousands
of chemicals and their reactions
Can you think of any other chemicals that are in our
bodies which help maintain our ‘steady state’ ??
How do these chemical
exchanges/reactions take place??
• What are the 2
environments which
are important in
maintaining
homeostasis?
• External environment
& internal
environment
What would happen if homeostasis
were not maintained??
Sickness and eventual
death of the organism
Levels of Body Structure
What is an ‘Organ System’?
Organ System • Multiple organs that
together perform a vital
body function.
• What level of structure is
higher than an organ
system?
• The whole organism!
• What are some organ
systems that you can
think of? There are 12 !
Integumentary System
• Largest organ yet only
about 2mm thick!
• Epidermis – outer most
layer; dead cells
• Melanin – bottom region
of the epidermis; cells are
alive and give skin its
color
• Dermis- skin layer below
the epidermis, supports
the epidermis
• Hypodermis- tissue layer
below the dermis which
contains adipose tissue
(fat-storing cells and
blood vessels)
Skeletal System
Provides strong
framework and
maintains body shape.
The backbone (spinal
cord) consists of
vertebra and cartilage.
Included in this
system is ligaments
Bones contain tissue
called marrow.
Muscular System
• Many different kinds
of muscles (i.e.
skeletal, cardiac,
smooth, etc.)
• Included in the
system are tendons
(connective tissue
which holds muscle to
bone)
Digestive System
• Breaks down food
to enable nutrient
absorption.
• Needed for reabsorption of
water in the body.
• Consists of
multiple organs
Circulatory System
Circulation, transportation and distribution of materials.
What kind of materials???
Respiratory System
Allows gas exchange because cellular
respiration requires…………..
Nervous System
Allows the body to
sense, feel and
coordinate its
movement.
Consist of many
different kinds of
neurons which
serve different
purposes.
Lymphatic System
• Collects and returns
most of the blood
which leaves the
circulatory system
into the interstitial
tissue.
• This collected fluid is
called lymph
Immune System
• Protects the organism against disease
• Acts as a line of defense against pathogens
Endocrine System
• Endocrine glands
secrete regulatory
hormones (>40).
• These hormones
maintain homeostasis
• What are some
examples of
hormones and what
they regulate?
Excretory System
• Eliminates
metabolic
waste
• Regulates the
intake and
loss of water
• Role in
homeostasis?
Reproductive System:
producing offspring is necessary for survival of
the species
Major systems in animals
Digestive System & Nutrition (Ch. 29)
• What is the purpose of the digestive system?
• How does it accomplish this?
• What are the 2 types of digestion which take place in us?
• Mechanical- the physical breaking down of food.
• Chemical- the breaking down of the chemical bonds of
larger molecules to produce smaller molecules which our
body can absorb.
Types of Digestion video
Nutrition : Heterotrophic creatures must obtain
materials for energy and synthesis
4 Stages of food
processing:
Ingestion
Digestion
Absorption
Elimination
Is this true in
humans as well?
Alimentary Canal Systems: tube-within-a-tube body plan
•Ingested food enters mouth and is digested extracellularly in
the organs of the systems.
•The end products of digestion are absorbed into transport
system.
Human Digestive System
Mouth:
Ingestion and mechanical digestion when food is chewed
Mechanical digestion increases surface area
Chemical digestion of starches due to amylase in the saliva
Digestion in
Mouth video
Swallowing Reflex
How is the food kept out of trachea?
Esophagus: peristalsis pushes food down;
no enzymes here only mucous.
Stomach: Begins digestion of protein with protease enzymes.
Gastric juice: contains hydrochloric acid (pH 2-3)
Malfunctions: Heartburn and Ulcers
What happens in the Stomach video
Small Intestine begins with the Duodenum
Bile made by liver is stored in the gall bladder. Emulsify fats.
Pancreas releases bicarbonate which neutralizes acidic chyme
Pancreas adds many enzymes to the small intestine.
What Happens in the Small Intestine video
Small Intestine
Complete chemical digestion with enzymes.
Villi provide high surface area for absorption of digested nutrients
Role of Circulation video
Large Intestine: absorption of fluids released into alimentary canal. Home
to symbiotic bacteria (E. coli).
Malfunctions: diarrhea and constipation
Appendix is vestigial
Rectum: storage of feces
What Happens in the Large Intestine video
Final Stages video
Enzymes of the digestive system
Malfunctions of the Digestive System:
Ulcers: erosion of the surface of the alimentary canal
Constipation: too much water is reabsorbed and solid waste
hardens, elimination is difficult
Diarrhea: decreased water re-absorption and increased
peristaltic activity in the large intestine. Results in increased,
multiple, watery feces. Dehydration possible
Digestive System Accessory Organs
Appendicitis: inflammation of the appendix due to infection
Gallstones: accumulation of hardened cholesterol and/or calcium
deposits in the gall bladder.
NUTRITION
Why is nutrition important to an organism?
Why do we eat?
Essential Nutrients: required materials animals must consume
Why must we consume them?
What happens when your diet is deficient in these nutrients?
Carbohydrate: roughage, starch and sugars
Fats: fatty acids, cholesterol
Proteins: amino acids
Vitamins: coenzymes, water and fat soluble
Minerals
Water
Maintain a Healthy Body
video
Closer Look at Nutrients
Video
Eating disorders and their effects
• Malnutrition: deficiencies of essential
nutrients. Ex: lack of Vit. C ->……..?
• Undernutrition: not enough calories/food
energy in diet
• Obesity: being seriously overweight can
increase your risk of………….
• Eating Disorders: Bulimia, anorexia,
binge/purge – can ultimately result in …….
Integumentary System (skin &….)
• Epidermis – outermost layer;
mostly dead cells
• Melanin- pigment containing cells
which are found in the bottom-most
layer of epidermis
• Dermis-supports the epidermis;
mostly made of fibrous connective
tissue (elasticity); contains hair
follicles, nerve endings, sweat glands,
blood vessels
• Hypodermis-contains adipose
tissue which includes fat storage and
blood vessels
Integumentary System
• Hair and Nails – also part of this system; made of keratin.
• How does your hair maintain homeostasis?
Protects head from UV radiation from the sun
Provides layer of insulation from changing outside temps
Are there any other functions of hair?
Integumentary System
How is the skin important ?
Physical barrier against dirt and microorganisms
entering the body
Acts as insulation (layers!)
Cushions internal organs against injury
Maintains homeostasis by regulating body
temperature and water content
Is this system foolproof??
Skeletal System
• Bones are organs made
up of living connective
tissue!
• Bone matrix (giving
bones rigidity) is made
up of collagen, calcium
and phosphate.
Skeletal System
Marrow: cells found inside
large bones; yellow
marrow (fat storageenergy supply), red
marrow (new blood cells).
Ligaments: strong fibrous
connective tissue holding
2 bones in a movable
joint together.
Cartilage: softer than bone;
offers cushioning
protection where 2 bones
come together.
Bones and Cartilage
Skeletal System
• Movable joints:
– Pivot joint: where one bone
can rotate around another
– Ball & socket joint: enables a
bone to rotate back and forth
and side to side [allows
greatest range of motion]
– Gliding joint : allows bending
and flexing movement
– Hinge joint: allows only back
and forth movement
Can you think of some
examples of these types of
joints?
Skeletal System Disorders
arthritis: inflammation – joints become
swollen, stiff and sore
[rheumatoid arthritis is an immune system
disorder]
osteoporosis: bones become thinner,
porous and brittle.
Consume calcium now!!!
Muscular System
Works in conjunction with the skeletal system (connected to
bone by tendons)
Why is this system important for us?
Muscular System
Allows LOCOMOTION:
Muscular System
• Muscles can only pull –
cannot push
• Muscles work in pairsantagonistically
• Triceps relaxed and
biceps contracted.
Muscular System
• Muscle fiber is made of
smaller units called
myofibrils
• Myofibrils are made up of
repeating units called
sarcomeres.
• Sarcomeres are the basic
unit of action-it is the unit
that contracts and is made
up of 2 kinds of filaments:
thin (actin) and thick
(myosin)
Muscle Contraction
• As sarcomeres shorten, the muscle contracts.
End of Chapter 27
Review ?