Introduction to Human Digestive System

2. Human Digestive Systems Objectives
Describe how the human
Digestive system is organized.
Identify the importance of
Digestive system .

3. How is the human body organized?
Organization of the Body

4. The levels of organization in a multicellular
organism include:
 cells
 tissues
 organs
 organ systems
Organization of the Body

5. Every cell in the human body
is both an independent unit and a
co-dependent part of a larger
community—the entire organism.
Organization of the Body

6. Cells
A cell is the basic unit of structure and
function in living things.
Individual cells in multicellular organisms
are specialized.
Specialized cells are suited to perform
a particular function.
Organization of the BodyOrganization of the Body

7. Tissues
A group of cells that perform a single
function is called a tissue.
There are four basic types of tissue in
the human body: epithelial, connective,
nervous, and muscle.
Organization of the BodyOrganization of the Body

8. Organization of the Body
Organs and Organ Systems
A group of different types of tissues that
work together to perform a single
function is called an organ.
A group of organs that perform closely
related functions is an organ system.
There are eleven organ systems in the
body.
Organization of the Body

9. The 11human body systems
1. -- Nervous system
2. -- Integumentary system
3. -- Respiratory system
4. -- Digestive system
5. -- Excretory system
6. -- Skeletal system
7. -- Muscular system
8. -- Circulatory system
9. -- Endocrine system
10. -- Reproductive system
11. -- Lymphatic (immune) system

10. Digestive system
Digestion is chemical and
mechanical process on the
ingested (consumption) food to
prepare it for absorption by the
body.

11. Function of Digestive System
oIngestion
oChewing
oSwallowing
oDigestion
oAbsorption
oExcretion of undigested food
Digestive system

12. Organs of Digestive System
 Mouth
 Pharynx (Throat)
 Esophagus (Food tube)
 Stomach
 Small intestine
 Large intestine
 Rectum
Digestive system

13. Heart Position

14. Layers of Digestive System
 Inner Epithelial layer
 Secretion of enzyme and mucus
 Soft and pink in colour
 Middle Muscular layer
 Outer layer (Longitudinal muscles)
 Inner layer (Circular muscle)
 Peristalsis (Segmental contraction)
 Outer Serous layer
 Protective function
Diagram

15. Organs of Digestive System
oMouth
Beginning of Digestive system
Lips, teeth, gums,tongue.
Palate (soft and hard)
Opening of Salivary glands
oTeeth
Total 32 in adults
oTongue
Helps in mastication
Mixing all saliva with food
Swallowing , Sensation of taste
Speech

16.  Salivary glands
 3 pairs
 Parotid in front of ear
 Submandibular below lower jaw
 Sublingual below tongue
 Saliva
 Secretion of salivary glands
 Converts starch into sugar
 Swallowing
 Voluntary and Involuntary stages:-
 Voluntary
 Bolus formation
 By movement of tongue and cheeks
 Bolus pushed into pharynx
 Involuntary
 Glottis contracts and closes
 Food passes to Oesophagus
 Breathing ceases during this step

17.  Esophagus
 25cm long muscular tube
 From pharynx to stomach
 Behind trachea and in front of
vertebral column
 Major part passes to Thorax
 Food passes to stomach by
active muscular action
 Solid food reaches stomach in 7
to 8 seconds
 Liquids reaches stomach in 2 to
3 seconds

18.  Stomach
 Dilated part of Digestive system
 Lies in upper abdomen below
diaphragm
 Slightly left to midline
 Upper opening connected to
Oesophagus
 Lower opening connected to
Duodenum
 Both remain closed during gastric
digestion
 J shaped in standing position
 Elastic muscular bag with capacity of
2 liters

19.  Liver
 Functions
 Synthesis of bile
 Formation of urea
 Detoxification of drugs
 Destruction of RBC
 Storage of excess glucose in form
of glycogen
 Storage of Vitamin A & D
 Storage of Hemoglobin
 Manufacturing of blood proteins,
albumin & globulin
 Manufacturing of prothrombin &
fibrinogen

20.  Gall bladder
 Stores the liver bile (60ml)
 Pancreas
 Located in upper
abdomen behind the
stomach
 Right part in the C of
Duodenum
 Extends to the left up to
the spleen
 Manufactures digestive
enzymes
 Manufactures insulin

21.  Small intestine
 6 to 7 meter long,
 2.5cm diameter
 Lies in center of abdomen
 Alkaline Secretions(Anti acid)
 Protects from acid contents of
stomach
 Small intestine
 Mucosa
 Deeply folded to increase the
surface area
 Helps in absorption of food

22.  Large intestine
 1.5meter long, 5 to 6cm
diameter
 Divided into 3 parts
 Right ascending colon
 Transverse colon
 Left descending colon
 Sigmoid Colon & Rectum
 Temporary storage of
fasces(poop)
 Anus is guarded by external
& internal sphincters

23. Video On Human Digestive system

24. Question & Answer
1. Our throat divides into two separate tubes: the
windpipe and the gullet.
What prevents food from entering the windpipe?
a) The uvula
b) The tongue
c) The trachea
d) The epiglottis

25. 2. Which of the following does NOT manufacture
digestive juices?
a) Liver
b) Kidneys
c) Stomach
d) Pancreas
Question & Answer

26. 3. All of the following are organs of the
digestive system except the
a) spleen
b) liver
c) tongue
d) esophagus
Question & Answer