Unit 4

Internal Systems

Digestive System! Metabolism; chemical reactions that occur in living organisms that are necessary to maintain life. ! Cetabolism; the metabolic reactions that break down larger molecules.! Anabolism; metabolic reactions that produce larger molecules. ! Metabolic rate is the rate at which the body converts stored energy into working energy. Factors that affect metabolic rate are body size, physical activity, gender, age, and genetics. ! Vitamins are compounds that an organism needs as a nutrient in only small amounts! • Can be fat or water soluble! • Most are obtained from food, some produced by body! Minerals are naturally occurring elements that our bodies use to carry out metabolic processes and to build/ repair tissues.!

Carbohydrates! • • • • •

Main source of energy for humans, also called sugars! Made of C, H, and O! Monosaccharides have one molecule. Ex glucose! Disaccharides have two molecules. Ex lacose! Polysaccharides have many molecules. Ex glycogen and starch!

Proteins! • Structural molecules, key building blocks of body! • Involved in metabolic activities! • Complete polymers, made of amino acid monomers!

Lipids (fats)! • Concentrated source of chemical energy for the body! • Structural component of cells and some hormones! • Unsaturated Fats; oils, liquid at room temperature (Good fats)! • Saturated fats; solid at room temperature (butter)! Function of the digestive system! • Ingest food! • Digest food! • Absorb nutrients! • Eliminate indigestible remains! Mechanical digestion is where large pieces of food become smaller pieces to increase surface area. Ex chewing! Chemical digestion is where enzymes break down macromolecules to small organs molecules that can be absorbed. ! Bolus is a smooth lump after mechanical and chemical digestion in the mouth.! Esophagus is the muscular tract leading from mouth to stomach.! Peristalsis are wave-like muscular contractions and relaxations to help move food smoothly, even against the force of gravity. ! Esophageal sphincter is a muscular ring that controls entry into the stomach.! Stomach is a J-shaped sac, where muscles and secretions work to physically and chemically break down food, and push it in to the small intestine. !

Unit 4 Internal Systems Chyme is the thick liquid formed by mixing food and gastric juices in stomach.! Pyloric sphincter acts like a valve between stomach and small intestine. ! Gastric juices include mucus, acid and digestive enzymes. They are signalled when nerves in the stomach detect food.! Ulcers are erosions in the lining of the stomach or duodenum caused by bacteria.! Small intestine completes the digestion and absorbs nutrients. Composed of:! • Duodenum is the first 25cm, chemical digestion of chyme occurs.! • Jejenum is where absorption of nutrients occur! • Ileum is where water absorption occurs! Villi are finger-like projections along the ridges of the small intestine that increase surface area and allows for more absorption. ! Microvilli are projections on the villi that increase surface area as well.! Large intestine is about 1.5 meters long, and mainly absorbs water. Composed of:! • Caecum, colon, rectum, and anal canal! Anal sphincter is a muscular ring that controls the movement out of the body.! Liver is the largest organ. Its main functions are to detoxify, store glycogen and vitamins, and produce bile which emulsifies fat! Ammonia is the toxic breakdown of proteins. Converted into urea by liver and transferrer to kidneys! Gall bladder stores bile produced by liver, and secretes it into the duodenum. ! Pancreas produces and secretes digestive juices to small intestine. Hormones are also produced here.! • Chyme entering the duodenum is acidic, activates prosecretin and stimulates the liver to make bile, and the pancreas to secrete bicarbonate to neutralize.! Hormones! Cholecystokinin (CCK) is signalled by chyme entering the duodenum. CCK enters bloodstream and signals pancreas to secrete pancreatic juice. CCK also signals stomach to slow the speed of digestion.! Secretin signals liver to make bile.! Enzymes! Amylase breaks down carbs. It is produced in the mouth and small intestine.! Pepsin breaks down protein. It is produced in the stomach. It inactive form is pepsinogen, which gets turned into pepsin in acidic environments.! Trypsin breaks down protein. It is produced in the pancreas and digests in the small intestine. ! Lipases break down fat. It is produced in the pancreas and digests in the small intestine.!

! ! ! ! ! ! !

in stomach

Unit 4

Internal Systems

Respiratory System! Four features of a respiratory system! • Large surface area! • Permeable membrane! • Good supply of blood! • System to bring air to membrane! The Nose! • Lined with hair to trap large dust particles! • Has mucus membranes to moisten air and ! trap small dust particles! • Ciliated cells line nasal passages. They have little hairs to move mucus to throat! The Mouth! • Warms the air but does not add moisture or filter dirt and dust particles! • Pharynx connects nose to mouth. ! • Tonsils and aderiods are tissues that fight bacteria and viruses.! Larynx has thin membranes that vibrate to make sounds as you exhale (voicebox)! • The Trachea! • Reinforced with cartilage rings, lined with a mucus membrane! • Divides into two bronchi; each bronchus leads to a lung! • Bronchi divide into smaller tubes called bronchioles! The Lungs! • Each bronchiole ends in an alveolus (alveoli)! • Alveoli are very small, inflatable sacs. During inhalation, they expand! • Lungs are pink at birth but get damaged with age, pollution and smoking! Lung tissue is elastic, easily inflated and deflated. !

Ventilation! • Breathing is the physical movement of the air into and out of the lungs.! • The diaphragm is a dome shaped muscle that contracts, pulling the lungs down and making a negative pressure, forcing air into the lungs. ! • When the diaphragm relaxes, it forces air out of the lungs! • Intercostal muscles between the ribs contract during inhalation, which forces chest cavity up and out.!

! ! ! ! ! ! ! ! ! ! ! !

Unit 4

Internal Systems

! !

Partial Pressure! Two factors govern respiration:! • Surface area! • Difference in concentration of gases across membrane! Composition of gases in air does not change at different altitudes ! • Oxygen composes 20.9% of air, Carbon dioxide composes 0.0391% of air! Total air pressure is the sum of partial pressures of gases! • If air pressure is 101.3kPa, Po2= 101.3 x 0.209, = 21.17kPa ! Partial pressure affects gas exchange! • Gases will diffuse across a membrane from high to low pressure! • The greater the gradient (difference), the faster diffusion will occur. !

! ! ! ! !Pco =5.6kPa

! Alveolus! Po=13.3kPa

2

Po=5.33kPa

! ! ! !

Pco2=5.33kP

! !

!P !

a 3.3kP Po=13kPa 5.3 co2=

Blood leaving lungs

Pco2=5.6kPa Po=5.33kPa Body Cell

• Circulatory system transports oxygen by hemoglobin (98.5%) and dissolved in plasma (1.5%)! • Hemoglobin increases blood’s ability to carry oxygen by 70 times! • Once at the cells, dissolved oxygen diffuses first, causing oxygen in hemoglobin to dissolve in plasma, then diffuse into cells. ! • CO2 transports via! • 7% dissolves in plasma! • 20% attaches to hemoglobin (carbaminhemoglobin) ! • 73% reacts with water in plasma to form carbonic acid! Altitude! • Above 7000m, pressure is too low for humans to survive! • At high, but livable, altitudes, rate of diffusion is lower, so body increases production of hormone erythropoietin (EPO)! • EPO stimulates production of red blood cells! • Increased red blood cells allows for an increased amount of oxygen to be carried! Breathing control! • Breathing in controlled by nervous and circulatory system! • Levels of CO2 and O2 are regulated by chemical receptors in brain, arteries leading to brain, and arteries !

! ! !

Unit 4

!

Internal Systems

Circulatory System! • Has fluid that transports materials through body! • Network of tubes for the fluid to circulate! • Pump! Arteries have high pressure! • Carry blood away from heart! • Three layers of tissues make up the wall! Veins are low pressure! • Carry blood back to heart from body! • Thin walls! • Valves keep blood from flowing backwards! Capillaries ! • Single cell wall to allow diffusion! • Small vessels that branch out to ensure all cells receive oxygen and nutrients! Vasodilation ! • Smooth muscles in the arterioles in the skin relax, which allows increased blood flow to skin, which is a cooling strategy! Vasoconstriction! • Smooth muscles contract, narrowing diameter and restricting blood flow! • Directs blood to where it is needed! Varicose Veins! • Less muscular! • Larger diameter! • Lower pressure!

The Heart! Structure: Muscular organ about the size of a fist! Function: rhythmically pumps blood through circulatory system! Four chambers! • Two atria receive blood returning to heart! • Two ventricles release blood for delivery to body (thicker muscle wall)!

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

Unit 4

!

Internal Systems

Systematic circulation (to and from cells)! • Oxygenated blood pumped to the cells! • Deoxygenated blood carried back to the heart! • Delivers oxygen and nutrients!

Pulmonary circulation (to and from lungs)! • Deoxygenated blood from the body going to heart, then pumped into lungs! • Oxygenated blood going to the heart, to be pumped to the rest of the body! • Delivers waste CO2 and picks up oxygen!

Coronary circulation (circulation within the heart)! • Without it, heart muscle will die! • Heart will not be able to pump blood! • Blockage to coronary arteries will result in death of cardiac muscle, leading to a heart attack!

Heart Valves! • Open and close to ensure blood flows in one direction! • Controlled by pressure gradient (high—> low pressure)! • Disorders where valves to not work properly may be remedied using pig valve transplants and synthetic implants! • Tricuspid valve leads from right atrium to right ventricle (atrioventricular)! • Pulmonary valve leads from right ventricle to pulmonary artery (semilunar)! • Bicuspid valve leads from left atrium to left ventricle (atrioventricular)! • Aortic valve leads from left ventricle to aorta (semilunar)!

Heart beat sounds! • Sounds come from the closing of the heart valves! • LUBB sound is the atrioventricular valves closing! • Occurs as ventricles begin to contract! • DUBB sound is the semilunar valves snapping shut! • Occurs as ventricles relax; prevents backflow!

Blood Pressure! • Blood in under pressure in the blood vessels because the pumping of our heart! • Heart muscle contracts and relaxes in coordinated rhythm; cardiac cycle (0.8s)! • Contraction is called systole! • The ventricles, that are filled with blood, contract, pushing blood out! • Valves between atria and ventricles are closed! • Blood pressure increases; systolic pressure! • Relaxation is called diastole! • Blood enters atria and flows into ventricles! • Valves between atria and ventricles are open! • Blood pressure is low; diastolic pressure!

Nodes! • Stimulate the atria and ventricles to contract! • Contraction is initiated by electrical nerve impulses at the SA (sinuatrial) node; acts as a pacemaker to set heart rhythm! • Located where vena cava enters the atrium! • Electrical nerve impulses from the SA node are sent to the AV node (atrioventricular); atria then contract!

Unit 4

Internal Systems

• Electrical nerve impulses get sent from AV nodes to ventricles through Purkinje fibers; ventricles then contract! Blood flow through the heart! From lungs to body! • Pulmonary veins! • Left atrium! • Bicuspid valve! • Left ventricle! • Aortic semilunar valve! • Aorta! From the body to lungs! • Vena Cava! • Right atrium! • Tricuspid valve! • Right ventricle! • Pulmonary semilunar valve! • Pulmonary artery!

Plasma! • Transparent liquid that carries blood through system! • Electrolytes are simple inorganic salts that minimize changes in acidity! • Proteins in plasma! • Immunoglobins are antibiotics (disease fighting)! • Escort proteins! Transports wastes, nutrients, hormones and cholesterol! • Red blood cells— Erythrocytes! • 700x more red blood cells than white! • Carry oxygen to cells! • Transports CO2 to lungs! • Hemoglobin (iron) attaches to erythrocytes! • Identical in appearance and function! • Mature cells lose nuclei ! • Formed from stem cells; made in bone marrow! White blood cells— Leucocytes! • Phagocytic leucocyte! • Consume bacteria, viruses and dead cells! Lymphocyte! • • Creates antibodies to fight disease! T • cell Lymphocyte! • Makes proteins and fights disease! Vary in size and shape! • Platelets! • Clot blood when wounded! • Platelets clump at site! • Rebuild tissue!

Blood Types! • A, B, AB, O! • Each type has same antigen (protein markers on cell)! • Antigens induce formation of antibodies to fight foreign blood