Human Systems

Let’s talk digestion

Why do we need to digest food?

• To get the nutrients needed for our body to function by making it small enough to pass through our cell membranes.

– Major events of digestion:• Ingestion• Digestion• Absorption• Transport

Making molecules your own

• Most of the foods you eat are composed of plant or animal cells.

• When we digest foods we break them down into their smallest components (by way of hydrolysis).

• These components then can be reassembled into larger molecules that are useful to our bodies.

Molecule type Molecular form ingested Molecular form after digestion

Protein Protein Amino acids

Lipids Triglycerides Glycerol & fatty acids

Carbohydrates Polysaccharides, disaccharides, monosaccharide

Monosaccharide

Nucleic acids DNA, RNA Nucleotides

Molecules we eat to get the molecules we need

The roles of enzymes during digestion

• You have certain enzymes for specific food types.– They act as catalysts for reactions

• They help a reaction proceed at high rates in lower temperatures.

• Below are some examples of digestive enzymesEnzyme type Salivary amylase Pepsin (a protease) Pancreatic lipase

Source Salivary glands Stomach cells Pancreas cells

Substrate Amylose (starch) Proteins Lipids

Products Maltose & glucose Amino acids Glycerol & fatty acids

Optimum pH Neutral (pH 7) Acidic (pH 3) Neutral (pH 7)

Digestive system (alimentary canal)

Alimentary canal consists of:

•Mouth•Oesophagus (esophagus)•Stomach•Small intestine•Large intestine (colon)•rectum

Oesophagus (esophagus)• Food is first chewed by the mouth with the help of saliva which

carries amylase enzymes and is then swallowed down the oesophagus.

Food travels down the oesophagus by a

sequential series of smooth muscle

contractions: peristalsis

Stomach• Food is held here for a period of ~2hrs.• This is so gastric juices have a chance to mix the food.

– pepsin is most effective in lower pH’s so the hydrochloric acid not only breaks down food, & kills bacteria, but provides an environment for pepsin to be active.

Mucus lines the inside of the stomach to prevent damage that may be causes by the hydrochloric acid

Helps breakdown proteins

Small Intestine• When food finishes in the stomach it is

deposited into the 1st part of the small intestine called: duodenum

Trypsin (a protease), lipase, & bicarbonate

Pancreas, Liver, & Gall bladder

• Liver: makes & secretes bile to emulsify fats. The bile is sent to the duodenum. Stores excess glucose in the form of glycogen.

• Pancreas: secretes digestive juices (pancreatic lipase) in the duodenum.

• Gall Bladder: holds the bile until sent to the duodenum.

Villi of the small intestine

Why is your small intestine infested with villi?

Function of villi• Location of absorption of molecules

– All but the fatty acids are absorbed into the capillaries.– Fatty acids are absorbed into the lacteal.

• Lacteal is a vessel that is part of the lymphatic system

• Villi are thin for easy absorption & has an abundance of capillaries and lymph vessels.

• All absorbed molecules are taken to body cells by the circulatory system

• Nutrient molecule can be used for energy (glucose) or as a component to build a larger molecule (amino acids).– The process of building a bigger molecule is called: assimilation

Large intestine (colon)

• After the absorption of nutrients is finished in the small intestine; what is left moves through to the large intestine along with the water.

• Main function: water absorption• Home of bacteria Escherichia coli

– We provide food, water, & warm environment & they provide us with vitamin K & maintain a healthy environment for us.

• Anything left is eliminated as solid waste through the anus

Where does the breakdown of food end & the absorption of nutrients begin?

• While food is still being broken down in the duodenum, it begins to be absorbed by the lower part of the small intestine.

• By the time food is in the colon, it is no longer being digested, but water is still being absorbed.

Absorption vs Assimilation

• Absorption occurs when the food enters the body as the food molecules pass through a layer of cells and into the bodies tissues. This occurs in the small intestine which has many villi that are specialized for absorption.

• Assimilation occurs when the food molecules becomes part of the bodies tissue. Therefore, absorption is followed by assimilation.

What’s the difference between the digestive system & the

excretory system?

Excretory- filters excess salts, water, & nitrogenous waste out of the blood

stream.Digestive- breaks down & absorbs nutrients from

food.

Good things to eat for a good digestive system

FIBER, FOLIC ACID, & CALCIUM

Fiber

• Fiber is not digested by our body. It helps us not be constipated, helps lower cholesterol & glucose levels– There are 2 types:

• Soluble-dissolves in water & becomes gel-like; helps lower cholesterol by lowering low-density lipoprotein, or "bad," cholesterol levels & glucose levels by slowing the absorption of sugar.

– Apples, oats, citrus fruits, peas, beans…

• Insoluble- does not dissolve in water; promotes movement of material through digestive system

– Whole-wheat flour, wheat bran, nuts, and vegetables

How much fiber do you need?

• How much fiber do you need each day? The Institute of Medicine, which provides science-based advice on matters of medicine and health, gives the following daily recommendations for adults:

Institute of Medicine, 2012

Age 50 or younger Age 51 or olderMen 38 grams 30 gramsWomen 25 grams 21 grams

Folic acid (a type of vitamin B)

• Key for growth and metabolism• It aids in rapid cell division (which occurs in the

stomach lining)• Folic acid supplements are standard for pregnant

women and women who plan to become pregnant. – lower the risk of preeclampsia and early labor. – Reduces the risk for devastating birth defects of a baby’s

brain and spine -- spina bifida and anencephaly -- by 50% to 70%.

How much folic acid do you need?Category Folate (Folic Acid)

Recommended Dietary Allowance (RDA)

For children under 1, only an adequate intake (AI) is available

0-6 months 65 micrograms/day

Adequate Intake (AI)7-12 months 80 mcg/day

Adequate Intake (AI)1-3 years 150 mcg/day4-8 years 200 mcg/day

9-13 years 300 mcg/day14 years and up 400 mcg/day

Pregnant women 600 mcg/day

Breastfeedingwomen

500 mcg/day

The recommended dietary allowance (RDA) includes the folic acid you get from both the food you eat and any supplements you take.

How Do Essential Fatty Acids Aid the Body?

• Essential fatty acids (omega 3 and 6) assist in the development and function of the brain and nervous system, and they help regulate proper thyroid and adrenal activity. They play a role in thinning your blood, which can prevent blood clots that lead to heart attacks and stroke. They also possess natural anti-inflammatory qualities that can relieve symptoms of both arthritis and other autoimmune system diseases.

• Essential fatty acids regulate blood pressure, immune responses and liver function, as well as help with blood clotting and breaking down cholesterol. They also help you look good, as a diet low in these fatty acids has been shown to create skin problems, including eczema, dandruff, split nails and brittle hair.

Calcium

• Helps promote good teeth.Calcium Requirements

SCHOOL AGE CHILDREN AGES 4 TO 8 REQUIRE 1,000 MG OF CALCIUM PER DAY.

AS CHILDREN REACH PUBERTY, A TIME OF INCREASED GROWTH AND DEVELOPMENT, FROM AGE 9 TO 18, CALCIUM REQUIREMENTS INCREASE TO 1,300 MG EACH DAY.

DURING ADULTHOOD, AGES 19 TO 50, CALCIUM REQUIREMENTS DROP BACK TO 1,000 MG EACH DAY.

ADULTS OVER THE AGE OF 50 REQUIRE 1,200 MG OF CALCIUM PER DAY.

Digestive DisordersCeliac disease: the body's immune system is triggered by gluten in food. Antibodies attack the intestinal lining, damaging, flattening, or destroying the tiny hair-like projections (villi) in the small intestine. Damaged villi can't effectively absorb nutrients through the intestinal wall. As a result, fats, proteins, vitamins, and minerals get passed through the stool. Over time, this can lead to malnutrition.

Lactose Intolerance- body is lacking the enzyme (lactase) to break down the sugar in milk or other dairy products.

Constipation: Best avoided through regular exercise and a diet high in fiber from whole grains, fruits, and vegetables. To older folks, who tend to get constipated more frequently: Be sure you're hydrating properly and aware of any medications that might be causing the holdup.

A challenge….an inexpensive colon check up.

Eat a half cup of corn and record the date and time of consumption.

Keep an eye out for the corn to come out in your bowel movement.

While you are looking at your feces, observe the color, shape, density and frequency.

Checking your “poop”

Density:

Color:

Shape:

Frequency:

sinks floats/sinks slowly floats

Black-coffee brown coffee-with-cream yellowish brown

Rounded, small pieces size & shape of your colon diarrhea

Less than once per day 1-3 times/day 3+ times/day

IDEAL

Eat more fiberEat fewer processed foods

Eat less fiberLower your stress level

What about other organisms?

Gastrovascular Cavity

Mouth and anus are the same opening

Food is moistened and stored in the crop. Most of the digestion occurs.

Gizzard pulverizes food

Circulatory System

Pumps your blood!!!

The Human Heart“Pumps Your Blood”

Valves close to prevent backflow

Closing of the valves produces the “lub dub” sound of you heart

arterioles

venules

Why is the muscle thicker at the left ventricle?

Where would you suppose the highest blood pressure is and why?

Where would you suppose the lowest blood pressure is and why?

The aorta because this is the first place blood travels from the heart pumping it out.

Veins- this is the last area blood travels before entering the heart again. They have valves to prevent back flow

Control of your heart rate

• Hearts are made of muscle tissue; cardiac muscle.– Contracts & relaxes = myogenic muscle contraction

• Mass of tissue in the right atrium known as the sinoatrial node (SA node)– Acts as a pacemaker by sending electrical signals for the

artrias to contract (aka stimulate the myogenic contraction)• 2nd mass is known as the atrioventricular node (AV

node)– On a 0.1 second delay from the SA node in which it sends a

signal for both ventricles to contract.

What happens during exercise?

• Increased demand for oxygen so heart beat speeds up.

• Also an increased build up of CO2 in the bloodstream.

• The medulla chemically senses the rise of CO2

– sends signal through the cardiac nerve to the SA node to increase your heart rate

– Later sends another signal to decrease heart rate through the vagus nerve

Adrenaline

• Chemical that is able to influence your heart rate.

• High stress times and times of excitement triggers the adrenal glands to release adrenaline into your bloodstream.

• The SA node “fires” more frequently causing an increase in your heart rate.

The different blood vesselsArteries- take blood away from heart thick walled internal pressure is high

Veins- return blood from capillaries to the heart thin walled internal pressure is low have internal valves

Capillaries- thin walled (fits one cell at a time) all exchanges occur here internal pressure low

Valves close to prevent backflow

erythrocytes

leucocytes

Components of blood

WHAT IS TRANSPORTED BY OUR BLOOD?

NUTRIENTS HORMONESOXYGEN ANTIBODIES HEATCARBON DIOXIDE UREA

WHAT IS IN OUR PLASMA?

• 90% water• Salts in the form of dissolved ions (aka blood

electrolytes)– The concentration of these ions maintains osmotic

balance of the blood.• Human blood pH 7.4

– Plasma proteins- act as a buffer against pH change, help maintain osmotic balance, contributes to blood’s thickness (viscosity)

Vertebrate circulatory systems

Atherosclerosis

You are now going to diagram the circulatory system!!!!

Things to include:-Heart in detail 4 chambers

valves veins & arteries

-lungs & upper of lower body -arteries -arterioles

-veins -venuoles -capillaries

-make your diagram a circuit-indicate by color the deoxygenated

and oxygenated blood

You will do a presentation showing & naming the parts.Everyone in your group will talk.

The right atrium's where the process begins, Where the C02 blood enters the heart Through the tricuspid valve to the right ventricle The pulmonary artery and lungs. Once inside the lungs it dumps its carbon dioxide And picks up its oxygen supply Then it's back to the heart through the pulmonary vein Through the atrium and left ventricle."

"Pump, pump, pumps your blood.

"The aortic valve’s where the blood leaves the heart Then it's channeled to the rest of the bod

The arteries, arterioles, and capillaries too Bring the oxygenated blood to the cells The tissues and the cells trade off waste and CO2

Which is carried through the venules and the veins Through the larger vena cava to the atrium and lungs And we're back to where we started in the heart.

Pump, pump, pump, pumps your blood

Pump, pump, pumps your blood.

RESPIRATORY SYSTEM

GAS EXCHANGE

Anatomy of the respiratory system

Our lungs act together with our heart & blood vessels

Overview of our respiratory system

• Aerobic cell respiration

• Ventilation

Process of delivering oxygen to our cells and releasing CO2 -chemical bonds in a glucose molecule are broken to release energy.

Energy is then stored as ATP. -Process requires O2 & the C molecules in glucose are given off as a CO2 molecule

Breathing in air to our lungs and releasing CO2 into the air from our lungs -oxygen diffuses from the lungs to the bloodstream by way of the alveoli &

capillaries. CO2 diffuses the same way in reverse.

Why do we need a ventilation system for gas exchange? Why can’t we just take in oxygen by

diffusion through our cells?

Our bodies are too thick. Only the cells exposed to the outside would participate in the gas exchange.

Also, it ensures that the concentration of gases within the lungs encourages the diffusion of each gas in a direction that’s beneficial to our bodies.

Gas exchange within the alveoli

There are ~300 million alveoli in each of our lungs.

Where does the blood come from prior to entering the lungs?

Right ventricle

Diffusion of oxygen and carbon dioxide occurs simultaneously as long as you keep breathing; it replenishes the gases in the alveolus by keeping the concentration gradients

Structure & Function of the Alveoli

• The round shape provides a large surface area for the gasses to diffuse

• The thinness (single cell) of each alveoli as well as the capillary beds surrounding the alveoli allows for quick & efficient diffusion

• Moist inner lining (surfactants) of the alveolus allows the alveoli not to stick to each other & tear causing scar tissue.– Premature babies have not developed the surfactant &

need to be on a ventilator.

MECHANISM FOR BREATHING

Breathing is based on the inverse relationship between pressure & volume.- an increase in volume will lead to a decrease in pressure (& vice versa).

What muscles are involved in breathing?

DiaphragmAbdomen

Intercostal (surrounds the rib cage)

Draw the pathway that an oxygen molecule travels starting with going in

through the nose and ending with being delivered at a cell in your big toe.LIST AS MANY PARTS AS POSSIBLE

What about other animals?

Aquatic

Bony Fish

Blood flows in the direction opposite to the movement of water past the gills.As blood moves through a gill capillary it becomes more and more loaded with oxygen but it simultaneously encounters water with ever higher oxygen concentrations because the water is just beginning its passage over the gills.

It is a bit more difficult for gas exchange than for land animals. Why?

Density & O2 availability