Download Internal Systems and Regulation

Internal Systems and
Regulation
Nutrients, Digestion and Nutrition
Organs & Organ Systems
 Cells
 Tissues
 Organs
 Organ systems
 Organisms
 p. 205, tab. 1
Monitoring Organs
– X-rays  electromagnetic waves…what do they do?

Bismuth and barium
– CT scan  computerized axial tomography (p. 206)


Many x-ray pictures, computer assimilated to give cross sectional views and
3D images
Gases, solids and liquids can all be identified
– Nuclear imaging (p. 207)

Information about function as radioisotopes (radionuclides) collect in target
organs and emit radiation which is translated into a picture
– NMR  nuclear magnetic resonance technology


Structure and function of organs
NMR subcategory is MRI
– Uses the spinning motions of atomic nuclei to produce a map of the internal
structures of the body and how they are functioning
Obtaining Food

Essential Nutrients
– Heterotrophs – organisms that depend on
organic molecules manufactured by other living
things
– Autotrophs – nourish themselves using
inorganic material
Components of Digestion
Ingestion – taking in of nutrients
 Digestion – breakdown of molecules by enzymes
 Absorption – transport of digested nutrients to
tissues of the body
 Egestion – removal of wastes



Digestive Enzymes
Enzymatic reactions in the body are controlled by
temperature and pH
– Enzyme activity peaks at 37oC
pH effects on enzymatic activity
– Pepsin – low pH
– Amylase – neutral pH
– Trypsin – basic pH
Digestion Overview

Single celled organisms
(p. 209, fig. 3)
– Hydrolytic enzymes 
use water to break down
molecules

Simple multi-cellular
organisms (p. 209, fig.
4)
– Gastrovascular cavity –
holds and digests, wastes
out
Digestion Overview

Complex multi-cellular
organisms (p. 209, fig. 5)
– Alimentary canal 
specialized regions

Earthworm
– Pharynx  esophagus
 stomach (crop) 
(gizzard)  intestine
{hydrolytic enzymes
& transportation of
nutrients}  anus

Humans ~ 6.5 to 9m
in length
Ingestion


Mouth – chemical and mechanical digestion
Teeth
– 3 molars, 2 premolars, 1 canine, 2 incisors on
each side (4 total) of the top and bottom
– Tooth – has root and crown
• Enamel crown has Ca2+
compounds and is the hardest
substance in the body
• Dentin inside the enamel and
it has pulp (nerves and blood
vessels)
• Decay
• Tongue (p. 211, fig. 2)
• Papillae – contain the taste
buds (sweet, sour, bitter, salty,
umami)
Ingestion
Uvula – prevents food
from entering the pharynx
 Saliva
 3 pairs of salivary glands
which secrete saliva using
ducts

Ingestion

Esophagus
– Need to ensure trachea closes and that food passes into the
esophagus
 Epiglottis covers the glottis so this does not happen
– Circular and longitudinal muscles (24 cm)
– Bolus of food is moved along using peristalsis
 Wavelike, muscular contractions and relaxations
 Circular muscles over food relax while longitudinal in front of
food contract
 Circular muscles behind food contract while the longitudinal
muscles relax
 p. 212, fig. 4
– Mucin helps to move food along
– Regurgitation – movement of food back up to mouth
The Digestive Tract

Stomach
– Muscular, J-shaped organ whose lining is covered with gastric
glands

Glands secrete gastric juice
– Has 3 layers of muscle (not just the 2 in the esophagus) – circular,
longitudinal and oblique
– All 3 layers work to break up food in the presence of gastric juices
(mucus, HCl, pepsin) to form chyme



Mucus  protective layer
HCl  kills harmful substances and converts pepsinogen to pepsin
Pepsin  protein digesting enzyme
– Pyloric sphincter – controls movement of food from stomach to
small intestine.
– Ulcers  H. pylori bacteria

Endoscope and laser treatment
The Digestive Tract

Small Intestine
– Named due to small diameter (2.5 cm) not length (7m)
 Large intestine  diameter (7.6cm), length (1.5m)
– Permanent folds to increase surface area (p. 225, fig. 2)
 On these folds are villi which further increases the surface
area and secrete intestinal juices
 Also lacteal or lymph vessels in the villi which accept larger
fat particles
– Duodenum – U-shaped and is the shortest yet widest of
the 3 sections


It lacks oblique muscles
Pancreatic and bile ducts empty into this section
The Digestive Tract
Jejunum – 2.5m long
Contains more folds then the duodenum
Breaks down remaining proteins and
carbohydrates
Ileum – 3m long
Fewer and smaller villi
Continue digestion and move food into the
large intestine

Pancreas
– Acid causes prosecretin to be converted to
secretin which travels to the pancreas and
causes bicarbonate ions to be released
 pH from 2.5 to 9 which inactivates pepsin
– Source of enzymes that act on carbohydrates
(amylase), fats (lipases), and peptides
(trypsinogen).
– p. 218, table 1
Related Organ

Liver
– Digestive role of producing bile salts from cholesterol
 Bile breaks down fats and is stored in the gall bladder
– Released into small intestine and break up fat globules
–
–
–
–
–
into droplets
Allows for faster processing and absorption into
bloodstream
Demolitions expert – red blood cells
Storage of monosaccharides (glucose  glycogen) and
vitamins
Protein breakdown – elimination or conversion, converts
toxic N groups to urea
Detoxification – breaks down ingested poisons
The Digestive Tract

Large Intestine – 1.5m, diameter is greater though
– Caecum, colon, rectum and anal canal
– Caecum – blind end which leads to the appendix
– Colon – water and dissolved minerals are absorbed and
bacteria break down what is left
– Rectum – accepts feces and passes it along to the anal
canal (last 20 cm of large intestine)
– Anus – feces pass out of body

Anal sphincters help to control
How long does it take to digest food?

Twenty to 30 hours depending on food and
metabolic rate
– Mouth: Food stays in your mouth for about ten seconds.
– Esophagus: Food takes five to six seconds.
– Stomach: How long food stays in your stomach depends on the

food. Most food stays in the stomach between two and four hours.
– Small intestine: The food takes from five to six hours to pass
through the small intestine.
– Large intestine: The food takes from twelve to twenty-four hours
to pass through the large intestine.
– In total, food takes from twenty to thirty hours to pass through
your body.
Gum – is not digestible so it will pass through your digestive system
the same as any other non digestible item (i.e. coins, marbles).
How to improve your digestion

Item #1 to think about…
– Basic 1: Chew, Chew, Chew Take smaller bites.
– Put your fork down in between bites.
– Try using chopsticks - it forces you to slow down.
– Thoroughly chew each bite of food.
– Carbohydrate digestion begins in the mouth - chewing grains
thoroughly allows amylase, the digestive enzyme present in saliva,
to digest the grains.
How to improve your digestion

Item #2 to think about… Get Enough Water
Insufficient water intake is a primary cause of
constipation. Constipation then causes an
imbalance in bacteria, promotes inflammation of
the intestinal lining, and can even lead to the
absorption of larger molecules, a condition
known as intestinal permeability.
How to improve your digestion

Item #3 to think about….Increase Your Dietary Fiber
– Good sources of dietary fiber include: Dried fruit, such as dates, figs, and
prunes
– Beans and legumes- if you don't have time to cook dried beans, buy
canned, but make sure you rinse them thoroughly before cooking. Lentils
and split peas are less gas-forming than other legumes.
– Bring an apple with you to work as a snack
– Ground flaxseeds are a gentle laxative. They can be useful for chronic
constipation, damage to the intestine wall from laxative use, irritable
bowel, and to soothe inflammation. Sprinkle ground flaxseeds on rice,
grains, salads, or any other meal of your choice.
How to improve your digestion

Item #4 to think about …Address Food Sensitivities and
Allergies

Food sensitivities are behind many digestive disorders. For
example, between 33% and 66% of IBS patients report having one
or more food intolerances, resulting in bloating, gas, and pain. The
most common culprits are milk and dairy (40-44%) and grains
(40-60%).
A trained practitioner can supervise an elimination diet. Many
foods are removed from the diet for a brief period of time, then reintroduced sequentially to isolate the body's reaction to the
offending foods.

How to improve your digestion

Item #5 to think about…Increase Good Gut Bacteria
– Not all bacteria is bad. There are over 400 different kinds of bacteria and yeasts in the
digestive system. Of these, the bacteria Lactobacillus acidophillus and Bifidobacterium
bifidum are considered good "probiotic" bacteria because they can help to maintain
intestinal health.
– Although good bacteria can be found in some yogurt, there is a wide variation in the
quantity and quality. Look for good quality organic yogurt that add the active cultures
after pasteurization, because this heat process destroys both good and bad bacteria.
– Supplements containing acidophilus and bifidobacteria can be found in health food
stores. They are especially helpful for the following conditions: Irritable bowel syndrome
– Diarrhea
– Gas, bloating, flatulence
– Recurring vaginal yeast infections
– Bad breath
Bad bacteria
• Listeriosis is a life-threatening infection caused
by eating food contaminated with the bacterium
(germ) Listeria monocytogenes (Listeria).
• April 20, 2015, Blue Bell Creameries recall
• 10 affected, 3 died
Regulation of Secretions

Nerves and hormones are in charge
– Hormone = chemical regulator that is secreted in one part of the
body and transported to another part, where it causes a response.
– e.g. digestive glands on walls of stomach are stimulated by nerves
and by gastrin. In response, individual glands secrete mucin,
pepsin, HCl and lipases.

Further, chyme in duodenum stimulates ductless glands in
the walls of the duodenum to secrete hormone secretin.
– Secretin goes to the pancreas to stimulate duct cells there to release
alkaline fluid (sodium bicarbonate)
Knowledge is Power

How do we know what we know?
– William Beaumont (1833) took a patient who had been
shot in the stomach.
– Improperly healed into a fistula
– Foods was put in with a string attached
– Emotions linked to secretions
Homeostasis

Perfect internal situation
–
–
–
–

37oC, 0.1% blood sugar, pH of 7.35
How do we maintain this?
Sensors  coordinating centre (?)  regulator
Meal blood sugar increases  pancreas releases insulin 
insulin allows sugar to be absorbed by cells  in liver, glycogen
in formed
Homeostasis and Digestion
– Seeing, smelling and tasting produce gastric secretions
– Secretin released when food travels from stomach to small
intestine
– Speed of food movement


Large meal will cause receptors increase muscle movement of stomach to
move food out of stomach
Fatty meal will be identified and cause food to stay in small intestine longer
Food Energy

Using energy all the time
– Joules (J) or kilojoules (kJ) compared to calories
– 1 cal = 4.18 J
– BMR  basal metabolic rate
 p. 230, table 1

Metabolic Factors
– Metabolism is the sum of all the chemical reactions that
occur within body cells
– Differences?
– Energy uses (p.232, table 2)
– Dieting Dangers
Nutrients


Amino acids - there are 20, we can not make 10
Fats
– Get a bad name but we need them to help us absorb vitamins,
insulate, protect delicate organs, protect nerves, cell membrane

Vitamins – organic molecules that help change food into
energy
– Water soluble – can not be stored

C and B groups
– Fat soluble – can be stored


A, D, E, K
Minerals – elements that help change food into energy
– Ca, I, Fe, P, K, Na

Antioxidants  reduce the danger of oxygen free radicals
– FR – created by exposure to sunlight, Xrays, ozone, tobacco
smoke, etc.

Damage to genetic information
Digestive Disorders

Symptoms
– Bleeding
– Bloating
– Constipation
– Diarrhea
– Heartburn
– Incontinence
– Nausea and vomiting
– Pain in the belly
– Swallowing problems
– Weight gain or loss
Disorder
Cause
Symptoms
Treatment
Gallstones
• Overweight, age near or above
40, female, or pre-menopausal
• Caucasians
• A lack of melatonin could
significantly contribute to
gallbladder stones
• as melatonin both inhibits
cholesterol secretion from
the gallbladder, enhances
the conversion of
cholesterol to bile
•"gallstone attack“
•in which a person
may experience
intense pain in the
upper-right side of
the abdomen, often
accompanied by
nausea and vomiting,
that steadily
increases
• Surgery or medications
Cirrhosis of
liver
• In the Western World, chronic
alcoholism and hepatitis C are
the most common causes.
•Yellowing of the skin
(jaundice) due to the
accumulation of bilirubin
in the blood
•Fatigue
•Weakness
•Loss of appetite
•Itching
•Easy bruising from
decreased production of
blood clotting factors by
the diseased liver.
• Liver damage from
cirrhosis cannot be
reversed, but treatment
could stop or delay further
progression and reduce
complications.
Disorder
Cause
Symptoms
Treatment
Crohn’s disease
• Exact cause still
unknown, a combination of
environmental factors and
genetic predisposition
seems to cause the disease
• Abdominal pain may be the
initial symptom
• Diarrhea
• Fecal consistency may
range from solid to watery.
• In severe cases, an
individual may have
more than 20 bowel
movements per day and
may need to awaken at
night to defecate
•At the present time,
there is no cure for
Crohn's disease and
remission may not be
possible or prolonged if
achieved
• Elemental diet, proper
hydration, and smoking
cessation. Smoking
• Heartburn
• Regurgitation
• Trouble swallowing
(dysphagia)
• Less-common symptoms
include:
• Pain with swallowing
(odynophagia)
• Increased salivation
(also known as water
brash)
• Nausea
• Chest pain
• Only weight loss and
elevating the head of the
bed were supported by
evidence
• Medication
• Surgery
Gastroesophageal • Abnormal nerve or
muscle function in the
reflux disease
stomach which, in turn,
(GERD)
causes food and stomach
acid to be digested too
slowly.