Human Physiology
Unit Eight
Nutrition
Nutrient - a chemical substance
found in food used by the body to
promote growth, maintenance,
repair & health
Nutrition
The mechanisms through which
nutrients are processed are:
▪ ingestion
▪ digestion
▪ absorption
▪ transport
▪ utilization
▪ excretion
Nutrition
The general functions of nutrients
are to provide:
▪ energy (E) for body processes
▪ substances needed to build
macromolecules
▪ substances needed for
regulation
Nutrition
The five basic food categories are:
▪ grains
▪ fruits & vegetables
▪ meats (protein)
▪ dairy
▪ fats & oils
Digestion
The digestive tract is a tubular passage that extends from
the lips of the mouth, through the body, and terminates
with an anus
This system can be divided into three regions:
+ oral cavity
+ pharynx
+ alimentary canal
Digestion
The alimentary canal can be further divided into four
segments:
+ esophagus
+ stomach
+ small intestine
+ large intestine
Digestion
Associated with the system are four glands/organs that are
located outside the tube, but secrete fluids into the system
to aid in digestion:
+ salivary glands
+ liver
+ gall bladder
+ pancreas
Digestive System
Digestion
The function of the digestive system is to mechanically &
chemically breakdown food so that nutrients can be
obtained through absorption and energy can be released
Digestion
Mechanical digestion breaks the food into physically
smaller particles, while chemical digestion breaks
macromolecules into monomers
Digestion
The monomers and other nutrients are now small enough
to be absorbed through the wall of the digestive tract and
into the bloodstream where they will be distributed to body
cells for energy needs and building materials
Oral Digestion
Oral structures involved in
mechanical digestion:
* teeth
* tongue
* hard palate
* cheeks
Hard
palate
Tonsil
Uvula
Soft
palate
Tongue
Teeth
Oral Digestion
Oral structures involved in
chemical digestion:
* parotid salivary
glands
* submandibular
salivary glands
* sublingual
salivary glands
Parotid
salivary
gland
Submandibular
salivary gland
Sublingual
salivary gland
Oral Digestion
Hard
palate
Structures involved in
swallowing:
* soft palate &
uvula
* pharynx
* epiglottis
* esophagus
Soft
Uvula
palate
Pharynx
Tonsils
Epiglottis
Glottis
Esophagus
Oral Digestion
Deglutition (swallowing)
Alimentary Canal Histology
Serosa
Muscularis
externa
(longitudinal
muscle)
Mucosa
Submucosa
Muscularis
externa
(longitudinal
muscle)
Alimentary Canal Movements
Segmentation
Peristalsis
Alimentary Canal
Movements
Alimentary Canal
Esophagus
Diaphragm
Stomach
Stomach
Diaphragm
Cardiac
region
Esophagus
Fundic
region
Body
A aa
Lesser
curvature
Rugae
Muscle
layers
Pyloric
antrum
Pyloric
sphincter
Greater
curvature
Stomach Wall
Rugae
Gastric
pit
Mucosa
Gastric
gland
Submucosa
Muscularis
externa
Serosa
Stomach Wall
Cardiac or Pyloric
Gland
Mucous
cell
Parietal
cell
Chief
cell
G cell
Gastric
Gland
Activation of Pepsin
Control of Gastric Secretion
Control of Gastric Secretion
Stomach Disorders
Emesis - the forceful ejection
of stomach or duodenal
contents
Heartburn – condition in
which stomach contents are
allowed to move into the
esophagus, causing a burning
sensation
Stomach Disorders
Gastritis – inflammation of
the stomach lining caused by
food, alcohol, bacteria, drugs,
HCl or pepsin
Peptic ulcers – erosion of the
stomach lining caused by
bacteria, aspirin, HCl or
pepsin
Stomach Disorders
Bulimia – eating disorder in
which emesis is induced so as
to rid the body of the food
recently eaten
Anorexia – eating disorder in
which a person loses their
appetite because they believe
they are fat
Accessory Organ Anatomy
Liver
Common
hepatic
duct
Anterior
Gall
bladder
Posterior
Liver Function
The liver carries out a number of functions:
> degradation of toxins, drugs,
etc.
> cleaning bacteria and debris
from the blood
> produces and secretes plasma
proteins
Liver Function
The liver carries out a number of functions that
concern digestion:
> process the monomers of
digestion
> processes vitamins and iron
> produces bile
Accessory Organ Anatomy
Liver Function
Cirrhosis of the liver is the replacing of liver tissue
with connective tissue, reducing the function of the
liver
Liver Function
Cirrhosis can have several causes:
> viral (hepatitis)
> drug abuse
> trauma
Accessory Organ Anatomy
Gall bladder
Cystic
duct
Hepatopancreatic
duct
Hepatopancreatic
sphincter
Hepatic ducts
Common
hepatic duct
Common bile
duct
Pancreatic
duct
Pancreas
Duodenum
Small Intestine Anatomy
Small Intestine Physiology
Small Intestine
Physiology
Villus
Microvilli
(brush border)
Capillaries
Lacteal
Small Intestine
Physiology
Large Intestine Anatomy
Large Intestine Disorders
Diverticulitis
Diarrhea
Constipation
Flatulence