Unit 6 Human Body & Unit 6 Human Body & Organ SystemsOrgan Systems

VIII. SystemsProtection, Support, & Locomotion Integumentary System

◦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 SystemI. Blood

i. Red blood cellsi. Transport oxygen and come carbon dioxideii.Lack a nucleusiii.Contains hemoglobin

ii.White blood cells1.Defend the body against disease

II. Pathway of Circulationa.Three main types of blood vessels

i. Arteries1.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. Veins1.Large blood vessels that carry blood from the tissues back towards the heart

Respiratory SystemI. Functions

a.Process of gas exchangei. Mechanisms involving in getting oxygen to the cells of your body and getting rid of carbon dioxide

II. Alveolia.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.Mechanicsa.Diaphragm and muscles between your ribs enable you to breathe

in and breathe outb.Diaphragm is located beneath the lungs

IV.Control of Respirationa.Involuntary processb.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

Digestive SystemI. Functions

a.Disassemble food into its component molecules so it can be used as energy

II.Digestive Tracta.Mouth

i. Mechanical digestion: physical process of breaking food into smaller piecesi. Saliva: contains digestive enzyme called Amylace :Chemical digestion

b.Esophagusi. Connects your mouth to your stomachii.Epiglottis: flap of skin that prevents food from entering into the

respiratory tract.c.Stomach : Food remains in your stomach for two to four

hoursi. Lined with smooth muscleii.Chemical digestion : Gastric juices: pepsin and hydrochloriciii.Mechanical digestion : Muscular churningiv.Mucus lining in your stomach to protect from the gastric juices

a.Small Intestine : Muscular tube about six meters longi. Chemical digestion: carbohydrates and proteins

1.Enzymes secreted by the pancreas and liver aid in the chemical digestion2.Bile: made by the liver and helps break down fats

ii.Absorption1.Liquid stays in your small intestines about three to five hours and is slowly

moved along by peristalsisb.Large Intestine

i. Indigestible material goes to the large intestineii.Water absorption

1.Water and salts are absorbed leaving behind a more solid material2.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

Nervous SystemI. Basic unit: Neuron or Nerve cell

a.Conduct impulses and carry them toward the cell bodyb.Neuron is a long cell that consists of three regions

i. Cell bodyii.Dendrites: receive impulses & carry them toward the bodyiii.Axon: carries impulses away from the cell body

II. CNS : central nervous system – Brain & Spinal corda.Anatomy of the Brain

i. Cerebrum1.divided into two halves2.controls intelligence, memory, language, senses, skeletal muscle movements

ii.Cerebellum1.back of the brain2.controls balance, posture, and coordination - if injury movements become jerky

iii.Brain stem1.medulla oblongata: controls involuntary activities (breathing)

I. PNS: peripheral nervous system

a.Two divisionsi. Somatic system: relays information between your CNS and skeletal

musclesii.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 defenseA.skin and mucous membranes = physical & waterproof

barrier1.cells shed so microbes can’t colonize2.mucous traps microbes and airborne pathogens (especially in

respiratory tract)3.saliva – lysozyme to digest bacterial cell wall / stomach – low

pHB. White Blood Cells (WBC)

1.phagocytes – cells that engulf pathogens– contain lysosomes2.macrophages – large WBC that are able to change their shape

to surround an invader & take it in through the process of phagocytosis

C. Inflammatory Response1.Local injury or infection

1.vasodilation near injury or infection increases blood causing redness and heat

2.increased blood flow brings more WBC