Transcript Organ Systems - BartlettsBiology11C

Organ
Systems
Organization


Individual body units: cells
Similar cells work together as: tissues

4 main types of tissue:


Different tissues form an: organ


Epithelial, connective, muscle, nervous
Heart, stomach, kidney, small intestine
Organs work together forming: organ systems

Digestive system, Nervous System, Endocrine
System, Excretory System
System
 What

is a system?
Organ system: group
of organs that has
related structures or
functions
Organ Systems
Organ System
Major Organs
Major Function
Digestive
Esophagus, stomach,
intestines, liver,
pancreas
Mechanical and
chemical breakdown
of food
Respiratory
Lungs, trachea, blood
vessels
Gas exchange; bring
in O2, rid body of CO2
Circulatory
Heart, blood vessels;
arteries, veins,
capillaries
Transportation of
nutrients, gases &
wastes, defence
against infection
Digestive System

Breaks down food

Nutrients are absorbed
 Transported by circulatory system

Cells require nutrients for:
 Growth, maintenance and repair
4 Stages of Food Processing


Ingestion – taking in nutrients
Digestion – breakdown of complex molecules
into smaller components

Absorption – taking up of digested molecules
by cells

Egestion – removal of food waste materials
from the body
Gastrointestinal Tract

Human digestive system
– one long tube, open at
both ends

Is food ever really ‘in’ your
body?
Digestive System Pathway
– Esophagus – Stomach –
Small Intestine – Large Intestine –
Rectum – Anus
 Mouth
Ingestion
 Digestion
 Absorption
 Egestion

Enzymes/Secretions


Many important enzymes/secretions play a
role in the digestive system
Enzymes
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
Amylase (mouth) – breakdown carbohydrates
Pepsin (stomach) – begins digestion of proteins
Secretions
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Bile salts (liver) – break fat into smaller globules
Sodium bicarbonate (pancreas) – raises pH of
chyme (2.5 – 9.0) so intestines protected
Absorption of Nutrients

Primarily takes place in small
and large intestines


Glucose, amino acids, fatty acids, glycerol
Nutrients absorbed by
small intestine
 Finger-like projections called villi increase
surface area of small intestine x 10…
 Each villus has a capillary network, nutrients
travel through circulatory system and
delivered to cells