Transcript Unit 6 Human Body & Organ Systems

Unit 6 Human Body &
Organ Systems
Systems
Protection, Support, & Locomotion
 Integumentary System
VIII.
◦ Skin: main organ (largest organ)
◦ Two layers: Epidermis and Dermis
◦ Composed of four types of body tissues
 Epithelial - Outer layer of the skin
◦ Functions to cover surfaces of the body
 Connective - Consists of both tough and flexible protein fibers
◦ Serves as a glue, holding your body together
 Muscle
◦ Interacts with hairs on the skin to respond to stimuli (cold/fright)
 Nervous
◦ Helps us detect external stimuli (pain/pressure)
◦ Epidermis: outermost layer
 25 to 30 layers of dead, flattened cells that are
continually being shed
◦ Dermis: second principal layer
 Vascularized: Contains blood vessels, nerves, hair
follicles, sweat glands, and oil glands
◦ Subcutaneous layer
 Adipose (fat) tissue
 Attaches skin to underlying organs (muscles) & tissues
◦ Functions:
 Help maintain homeostasis by regulation your internal
body temperature

Skeletal System
◦ 206 Bones – 300 bones
in babies
◦ Functions
 Framework for the tissues
of your body
 Protects internal organs
◦ Bone cells
 Ossification: bone
formation (osteoblasts)

Muscular System
◦ Types
 Smooth muscle
◦ Walls of your internal organs, blood
vessels
◦ Functions: to squeeze, exerting
pressure on the space inside the
organ it surrounds to move material
◦ Involuntary muscle
 Cardiac muscle
◦ Heart
◦ Conduct electrical impulses
◦ Involuntary muscle
 Skeletal muscle
◦ Moves your bones
◦ Voluntary muscle
Circulatory System
I. Blood

i. Red blood cells
i. Transport oxygen and come carbon dioxide
ii.Lack a nucleus
iii.Contains hemoglobin
ii.White blood cells
1.Defend the body against disease
II. Pathway of Circulation
a.Three main types of blood vessels
i. Arteries
1.Elastic blood vessel that carry blood away from the heart
ii. Capillaries
1.Form a dense network that reaches every cell in the body
iii. Veins
1.Large blood vessels that carry blood from the tissues back towards the heart

I.
Respiratory System
Functions
a.Process of gas exchange
i. Mechanisms involving in getting oxygen to
the cells of your body and getting rid of
carbon dioxide
II. Alveoli
a.Bronchus (bronchi)  bronchioles  alveoli
i. Alveoli= are the sacs of the lungs where oxygen and carbon dioxide are
exchanged by diffusion between air and blood
III.Mechanics
a.Diaphragm and muscles between your ribs enable you to breathe
in and breathe out
b.Diaphragm is located beneath the lungs
IV.Control of Respiration
a.Involuntary process
b.Medulla oblongata = helps maintain homeostasis
i. Responds to higher levels of carbon dioxide by sending nerve signals to rib
muscles and diaphragm
ii.Nerve signals cause these muscles to contract and you inhale

I.
Digestive System
Functions
a.Disassemble food into its
component molecules so it can
be used as energy
II. Digestive Tract
a.Mouth
i. Mechanical digestion: physical
process of breaking food into smaller pieces
i. Saliva: contains digestive enzyme called Amylace :Chemical digestion
b.Esophagus
i. Connects your mouth to your stomach
ii.Epiglottis: flap of skin that prevents food from entering into the
respiratory tract.
c.Stomach : Food remains in your stomach for two to four
hours
i. Lined with smooth muscle
ii.Chemical digestion : Gastric juices: pepsin and hydrochloric
iii.Mechanical digestion : Muscular churning
iv.Mucus lining in your stomach to protect from the gastric juices
a.Small Intestine : Muscular tube about six meters long
i. Chemical digestion: carbohydrates and proteins
1.Enzymes secreted by the pancreas and liver aid in the chemical digestion
2.Bile: made by the liver and helps break down fats
ii.Absorption
1.Liquid stays in your small intestines about three to five hours and is slowly
moved along by peristalsis
b.Large Intestine
i. Indigestible material goes to the large intestine
ii.Water absorption
1.Water and salts are absorbed leaving behind a more solid material
2.Vitamin synthesis (vitamin B and vitamin K are synthesize by anaerobic bacteria
and then absorbed by the body)
iii.Elimination of wastes
1.18 to 24 hours in the large intestine the indigestible material (feces) reaches the
rectum and then the anus. 24 to 36 hours for your meals entire journey

I.
Nervous System
Basic unit: Neuron or Nerve cell
a.Conduct impulses and carry them toward the cell body
b.Neuron is a long cell that consists of three regions
i. Cell body
ii.Dendrites: receive impulses & carry them toward the body
iii.Axon: carries impulses away from the cell body
II. CNS : central nervous system – Brain & Spinal cord
a.Anatomy of the Brain

I.
i. Cerebrum
1.divided into two halves
2.controls intelligence, memory, language, senses, skeletal muscle movements
ii.Cerebellum
1.back of the brain
2.controls balance, posture, and coordination - if injury movements become jerky
iii.Brain stem
1.medulla oblongata: controls involuntary activities (breathing)
PNS: peripheral nervous system
a.Two divisions
i. Somatic system: relays information between your CNS and skeletal
muscles
ii.Autonomic system: carries impulses from your CNS to internal organs
(involuntary)
Immune System
I. Terminology
A. Pathogens – infectious agent, a germ, that causes disease or illness to its host:
Viruses/Bacteria/Fungi/Protist
B. Antigens – molecule considered foreign by the body’s immune system & may stimulate an immune
response
C. Antibodies – proteins manufactured by the immune system which recognizes and targets a specific
antigen.
 Production – many different lymphocyte exist
 Each type recognizes one specific antigen & responds by dividing rapidly to form clones
D. Immunity
 Active immunity – due to the production of antibodies by the organism itself
 Passive immunity – due to the acquisition of antibodies from another organism in which
active immunity has been stimulated (placenta or colostrum)
 Natural immunity – due to infection or from mother
 Artificial immunity - due to innoculation with vaccine
 Non-specific defense
A. skin and mucous membranes = physical & waterproof
barrier
1.cells shed so microbes can’t colonize
2.mucous traps microbes and airborne pathogens (especially in
respiratory tract)
3.saliva – lysozyme to digest bacterial cell wall / stomach – low pH
B. White Blood Cells (WBC)
1.phagocytes – cells that engulf pathogens– contain lysosomes
2.macrophages – large WBC that are able to change their shape
to surround an invader & take it in through the process of
phagocytosis
C. Inflammatory Response
1.Local injury or infection
1.vasodilation near injury or infection increases blood causing redness and
heat
2.increased blood flow brings more WBC