Unit 7 Outline - MR. CRAMER · Unit 7 Outline: The Digestive ... Unit 7: The Digestive System and Nutrition 12 * inner layer ... • Humans- 2 sets of teeth (baby or milk) teeth

Name: Date: Class:

Unit 7: The Digestive System and Nutrition 11

Unit 7 Outline: The Digestive System and Nutrition

The Digestive System: Mouth and Pharynx

♦ The Digestive System and Body Metabolism

•

� Breakdown of ingested

� Absorption of nutrients into the

•

� Production of cellular (ATP)

� Constructive and degradative

activities

♦ Organs of the Digestive System

• Two main groups

� canal- continuous

coiled hollow tube

� digestive organs

♦ Organs of the Alimentary Canal

• Mouth

•

•

• Stomach

• intestine

• intestine

•

♦ Mouth (Oral Cavity) Anatomy

• Lips ( )- protect the

anterior opening

• - form the lateral walls

• Hard palate- forms the roof

• Soft palate- forms the roof

• - fleshy projection of the soft palate

• - space between

lips externally and teeth and gums internally

• Oral cavity- area contained by the teeth

• - attached at hyoid and styloid

processes of the skull, and by the lingual frenulum

• Tonsils

� tonsils

� tonsil

♦ Processes of the Mouth

• (chewing) of food

• Mixing masticated food with

• Initiation of by the tongue

• Allowing for the sense of

♦ Pharynx Anatomy

• - not part of the

digestive system

• - posterior to

oral cavity

• - below

the oropharynx and connected to the esophagus

♦ Pharynx Function

• Serves as a for

air and food

• Food is propelled to the esophagus

by

� Alternating contraction of two muscle layers


* inner layer

* outer layer

Digestive System: Esophagus and Stomach

♦ Esophagus

• Runs from pharynx to

through the diaphragm

• Conducts food by peristalsis

(slow rhythmic squeezing)

• Passageway for only (respiratory

system branches off after the pharynx)

♦ Layers of Alimentary Canal Organs

•

� Innermost layer

� membrane

* Surface

* Small amount of

tissue (lamina propria)

* Small muscle layer

•

� Just beneath the mucosa

� Soft tissue with

blood vessels, nerve endings, and lymphatics

• Muscularis - smooth muscle

� Inner layer

� Outer layer

•

� Outermost layer-

peritoneum

� Layer of fluid-producing

cells

♦ Stomach Anatomy

• On the side of the abdominal

cavity

• Food enters at the

sphincter

• Regions of the stomach

� region- near the heart

�

� Body

� - funnel-shaped terminal end

• Food empties into the small intestine at the

• - internal folds of the mucosa

• External regions

� curvature

� curvature

• Layers of peritoneum attached to the stomach

� Lesser - attaches the

liver to the lesser curvature

� omentum- attaches

the greater curvature to the posterior body wall

� Contains fat to insulate, cushion, and protect

abdominal organs

♦ Stomach Functions

• for food

• Site of food

• Chemical breakdown of begins

• Delivers (processed food)

to the small intestine

♦ Specialized Mucosa of the Stomach

• Simple epithelium

� Mucous neck cells- produce a sticky

mucus

� Gastric glands- secrete juice


� Chief cells- produce -digesting

enzymes (pepsinogens)

� Parietal cells- produce

acid

� Endocrine cells- produce

♦ Structure of the Stomach Mucosa

• pits formed by folded mucosa

• and specialized cells are in

the gastric gland region

Digestive System: Small and Large Intestine

♦ Small Intestine

• Body’s digestive organ

• Site of absorption into

the blood

• Muscular tube extending from

sphincter to the ileocecal valve

• Suspended from the posterior abdominal wall by

the

♦ Subdivisions of the Small Intestine

•

� Attached to the

� Curves around the head of the

•

� Attaches anteriorly to the duodenum

•

� Extends from jejunum to

♦ Chemical Digestion in the Small Intestine

• Source of that are mixed

with chyme

� Intestinal cells

�

• enters from the gall bladder

♦ Folds of the Small Intestine

• folds called plicae circulares

• Deep folds of and submucosa

• Do not disappear when with food

• Submucosa has

patches (lymphatic tissue)

♦ Villi of the Small Intestine

• Fingerlike structures formed by the

• Give the small intestine more

♦ Microvilli of the Small Intestine

• Small projections of the

membrane

• Found on cells

♦ Nutrient Absorption Structures

• cells

• Blood

• Lacteals ( capillaries)


♦ Large Intestine

• Larger in diameter, but

than the small intestine

• the internal abdomen

♦ Functions of the Large Intestine

• Absorption of

• Eliminates undigested food from body as

• participate in food digestion

• Goblet cells produce

(lubricant)

♦ Structures of the Large Intestine

• - saclike first part

•

� Accumulation of lymphatic tissue; can become

inflamed (appendicitis)

� Hangs from the

• Colon

�

�

�

� S-shaped

•

• - external body opening

♦ Large Intestine Muscularis Externa

• Smooth muscle is reduced to

bands (teniae coli)

• Muscle bands have some degree of tone

• Walls are formed into

(pocket-like sacs)

Accessory Organs of the Digestive System

♦ Accessory Digestive Organs

• glands

•

•

•

•

♦ Salivary Glands and Saliva

• Saliva-producing glands

� glands- located

anterior to ears

� glands

� glands

• Saliva

� Mixture of and

serous fluids

� Helps form food bolus

� Contains salivary (begin

starch digestion)

� Dissolves chemicals so they can be tasted

♦ Teeth

• Purpose- (chew) food

• Humans- 2 sets of teeth

� (baby or milk) teeth

* 20 teeth fully formed by age 2

� teeth

* Replace baby teeth between the ages of 6-12

* Full set is teeth (some people

have no wisdom teeth)

♦ Classification of Teeth

•

•

•

•


♦ Regions of a Tooth

• - exposed part

� Outer

�

� cavity

•

� Region in contact with gum

� Connects crown to root

•

� Attached to the

� Root canal contains

and nerves

♦ Pancreas

• Produces a wide spectrum of digestive enzymes

that break down all categories of food

• Enzymes secreted into the

• fluid introduced with

enzymes neutralizes acidic chyme

• Endocrine products of

�

� Glucagons

♦ Liver

• gland in the body

• side of the body under the

diaphragm

• lobes suspended from the diaphragm

and abdominal wall by falciform ligament

• Connected to the

via the common hepatic duct

♦ Bile

• Produced by cells in the

• Composition

� Bile

� Bile pigment (mostly

from breakdown of hemoglobin)

� Cholesterol

�

�

♦ Gall Bladder

• Found in fossa of the

• Stores from the liver

• introduced into the duodenum

in the presence of fatty food

• can cause blockages


Peristalsis

Segmentation

Digestive System Processes

♦ Processes of the Digestive System

• - getting food

into the mouth

• - moving foods

through the digestive system

� - alternating

waves of contraction

� - moving

materials back and forth to aid in mixing

• digestion

� of food in the mouth

by the tongue

� of food in the stomach

� Segmentation in the

intestine

• Digestion

� Enzymes break down food molecules into their

building blocks

� Each major food group uses different enzymes

* are broken

to simple sugars

* Proteins are broken to

* are broken to fatty acids

and alcohols

•

� End products of digestion are absorbed in the

blood or

� Food must enter cells

and then into blood or lymph capillaries

•

� Elimination of

substances as feces

♦ Control of Digestive Activity

• Controlled by

(parasympathetic)

• Chemical and mechanical receptors located in

organ walls trigger reflexes

• Stimuli include:

� of the organ

� of the contents

� Presence of

products

• Reflexes include:

� Activation or inhibition of

glandular

� muscle activity

♦ Digestive Activities of the Mouth

• Mechanical breakdown


� Physical breakdown of food by

• Chemical digestion

� Food is mixed with

� Breaking of starch into

by salivary amylase

♦ Deglutition (Swallowing)

• phase

�

� Occurs in the

� Food is formed into a

� Bolus is forced into the pharynx by

the

• Pharyngeal-esophageal phase

� transport of

the bolus

� All passageways except to the stomach are

blocked

* blocks off the mouth

* Soft palate (uvula) blocks

the

* blocks the larynx

� moves the bolus

toward the stomach

� sphincter

opens when food presses against it

♦ Food Breakdown in the Stomach

• Gastric juice is regulated by

and hormonal factors

• Presence of food or falling causes the

release of gastrin

• causes stomach glands

to produce protein-digesting enzymes

• acid makes

stomach contents very acidic

♦ Stomach Digestion and Absorption

• Protein digestion enzymes

� - active protein digesting

enzyme

� - digesting milk protein

• Only and

absorption occurs in the stomach

♦ Propulsion in the Stomach

• Food must first be well mixed

• Rippling occurs

in the lower stomach

• Pylorus meters out

into the small intestine (30 ml at a time)

• Stomach empties in hours

♦ Digestion in the Small Intestine

• Enzymes from the brush border

� Break double into

simple sugars

� Complete some digestion

• enzymes- major

digestive functions

� Pancreatic amylase completes

digestion

� Carry out about of all protein digestion

(trypsin)

� Responsible for digestion (lipase)

� Digest acids (nucleases)

� Alkaline content

acidic chyme

♦ Absorption in the Small Intestine

• is absorbed along the

length of the small intestine

• End products of digestion

� Most substances are absorbed by

transport through cell membranes

� are absorbed by diffusion

• Substances are transported to the

by the hepatic portal vein or lymph

♦ Propulsion in the Small Intestine

• - major means

of moving food

• Segmental movements

� Mix with digestive juices


� Aid in propelling food

♦ Absorption in the Large Intestine

• No digestive are produced

• Resident digest

remaining nutrients

� Produce some vitamin

� Release

• and vitamins K and B are absorbed

• Remaining materials are eliminated via

♦ Propulsion in the Large Intestine

• Sluggish

• Mass movements

� , powerful movements

� Occur times per day

• Presence of feces in the

causes a defecation reflex

� anal sphincter is relaxed

� Defecation occurs with relaxation of the

(voluntary) anal sphincter

Nutrition

♦ Nutrition

• - substance used by

the body for growth, maintenance, and repair

• Categories

�

� Lipids

�

�

� Mineral

�

♦ Dietary Sources of Major Nutrients

•

� Mostly from

� Except: lactose ( ) and

glycogens (meats)

•

� Saturated fats- products

� Unsaturated fats- , seeds,

vegetable oils

� Cholesterol- egg yolk, , milk

products

•

� Complete- contain essential

amino acids

* Most from products

� Legumes and - incomplete

proteins

•

� Most are used as and

act with enzymes

� Found in all major

•

� Play many roles in the body

� Mineral-rich foods- ,

legumes, milk, some meats

♦ Metabolism

• Chemical reactions necessary to maintain life

� - substances broken

down to simpler substances

� - larger molecules built

from smaller ones

� Energy is released during

♦ Carbohydrate Metabolism

• Body’s preferred source to produce

• (blood sugar)- major

breakdown product and fuel to make ATP

♦ Fat Metabolism

• Handled mostly by the

� Use some fats to make ATP

* Must be broken down to

* In , acetic acid

is oxidized to produce H2O, CO2, and ATP

� Synthesize and

cholesterol

� Release products

to the blood

• Cells remove fat and cholesterol to build

and steroid hormones

♦ Protein Metabolism

• Proteins are by

body cells (used for most cellular structures)


• Ingested proteins are broken down to

• Cells remove to

build proteins

� proteins

are actively transported across cell membranes

• Amino acids are used to make only

if proteins are overabundant or if other sources are

low

♦ Cholesterol Metabolism and Transport

• Functions of cholesterol

� Form hormones and

vitamin D

� Major building block of plasma membranes

• produces most cholesterol (not diet)

• Cholesterol and fatty acids

freely circulate in the bloodstream

• Transported by lipoproteins

� Low-density lipoproteins ( ) to

body cells

� High-density lipoproteins ( )

from body cells to the liver

Cellular Respiration

♦ Cellular Respiration

• Oxygen-using events take place within the cell to

create from ADP

• leaves cells as CO2

• atoms combine with

Oxygen to form water

• Energy produced by these reactions adds a

to ADP to produce ATP

• ATP is broken down to

energy for cellular use

♦ Metabolic Pathways Involved in Cellular Respiration

• - energizes a glucose

molecule so that it can be split into two pyruvic

acid molecules and yield ATP

• cycle

� Produces most of the and

H2O from cell respiration

� Yields a amount of ATP

• transport chain

� removed during glycolysis

and the Krebs cycle are delivered to protein

carriers

� H is split into H+ and e

- in

mitochondria

� give off energy

in a series of steps to enable ATP production

♦ Production of ATP from Protein

• groups are removed from

proteins as ammonia

• Rest of the protein molecule enters the

cycle in mitochondria

• Liver converts ammonia to - eliminated

in urine

Metabolic Role of the Liver

♦ Role of the Liver in Metabolism

• drugs and alcohol

• Degrades

• Produce cholesterol, blood

(albumin and clotting proteins)

• Central role in

♦ Metabolic Functions of the Liver

•

� molecules converted

to glycogen

� Glycogen molecules in the liver

•


� Glucose released from the

after conversion from glycogen

•

� Glucose produced from

and proteins

• and fatty acids are picked

up by the liver

� Some for energy

for liver cells

� Rest are broken down into simpler compounds

and released into the

Metabolism and Digestive Homeostasis

♦ Body Energy Balance

• Energy = total

energy output (heat + work + energy storage)

� Energy intake- released during food

� Energy output

* Heat is usually about %

* Storage energy is in the form of

or glycogen

♦ Regulation of Food Intake

• Body weight is usually

stable

� Energy intake and output remain

about

• Mechanisms that regulate food intake

� Levels of in

the blood

�

� Body

� factors

♦ Metabolic Rate and Body Heat Production

• Basic metabolic rate ( )- amount of

heat produced by the body per unit of time at rest

• Factors that influence BMR

� area- small body has

higher BMR

� - males have higher BMR

� - children and adolescents

have a higher BMR

� Amount of

produced is the most important control factor

* More thyroxine means

metabolic rate

♦ Total Metabolic Rate (TMR)

• Total amount of

the body must consume to fuel ongoing activities

• TMR increases with an increase in

body

• TMR must calories consumed

to maintain homeostasis and maintain a constant

weight

♦ Body Temperature Regulation

• Most energy is released as

are oxidized

• Most energy escapes as

• The body has a narrow range of homeostatic

temperature

� Must remain between ° to ° F

(35.6° to 37.8°C)

� Body’s thermostat is in the

* Initiates heat-loss or heat-promoting

mechanisms

♦ Heat Promoting Mechanisms

• of blood

vessels

� Blood sent to deeper, more vital organs

• - contraction of

muscles produces heat

♦ Heat Loss Mechanisms

• Heat loss from the skin via

and evaporation

� Capillaries in skin with warm blood

� Evaporation of

cools the skin


♦ Digestive System Development

• Alimentary canal is a continuous tube by the

week

• Digestive glands bud from the mucosa of the

tube

• Developing fetus receives all nutrients through the

• Newborn- frequent feeding, inefficient peristalsis,

and vomiting is common

• Teething begins around age months

• Metabolism with old age

• Middle age digestive problems

�

� problems

• Activity of digestive tract in old age

� Fewer digestive

� slows

� and cancer more common

Unit 7 Outline - MR. CRAMER · Unit 7 Outline: The Digestive ... Unit 7: The Digestive System and Nutrition 12 * inner layer ... • Humans- 2 sets of teeth (baby or milk) teeth

Documents