IB Biology - Human Phys. questions

Distinguish between the ECG trace of the patient with hypokalemia and the patient with hyperkalemia

- hypokalemia has a flat T-wave whereas hyperkalemia has a heightened T-wave. hypokalemia's S-T interval is longer. - hypokalemia has narrower/faster QRS complex compared to hyperkalemia. Hypokalemia's baseline is overall lower than hyperkalemia

Qhich of the following events occurs during ventricular contraction? 1. The AV valve closes at the beginning of ventricular systole 2. The volume inside the ventricles increases during ventricular systole 3. The semilunar valves start off open, and close during ventricular systole 4. The pressure in the ventricles drops during ventricular systole.

1. The AV valve closes at the beginning of ventricular systole

Outline the events that occur within the heart that correspond to the QRS complex

1. the arrival of a signal at the AV node 2. transmission via conducting fibers/bundle of His/Purkinje fibers 3. The ventricles depolarize 4. atrioventricular valves close and the semilunar valves open 5. ventricular systole 6. contraction begins at the apex

What is the main function of the large intestine? A. Absorption of water B. Digestion of fats and proteins C. Absorption of nutrients D. Recycling of digestive enzymes

A. Absorption of water

Why do nutrient molecules enter the blood? A. Blood carries nutrients to cells. B. Blood converts nutrients into energy. C. Nutrients and oxygen are mixed by blood. D. Nutrients are stored in blood.

A. Blood carries nutrients to cells.

What causes heart ventricles to fill with blood? I. Atrial contraction II. Closing of atrio-ventricular valves III. Opening of semilunar valves A. I only B. I and II only C. II and III only D. III only

A. I only

What causes heart ventricles to fill with blood? I. Atrial contraction II. Closing of atrioventricular valves III. Opening of semilunar valves A. I only B. I and II only C. II and III only D. III only

A. I only

What are the conditions of the blood travelling through the pulmonary vein?

A. Oxygen levels are high, CO2 levels are low, and pressure is low

What are functions of the stomach, small intestine and large intestine?

A. The stomach digests proteins, the small intestine absorbs glucose, and the large intestine absorbs water

Which of the following is correct for lipase? A. triglycerides, pancreas, pH = 8 B. fatty acids, small intestine, pH = 7 C. triglycerides, small intestine, pH = 9 D. fatty acids, pancreas, pH = 9

A. triglycerides, pancreas, pH = 8

Which feature increases the absorption of glucose in the small intestine?

A. villi

The diagram shows the layers of the tissues in a transverse section of the human small intestine. Which is the layer labeled with the letter X? A. Mucosa B. Circular muscle C. Epithelium D. Longitudinal muscle

B. Circular muscle

Which blood vessel directly supplies oxygen to the heart muscle? A. Aorta B. Coronary artery C. Pulmonary artery D. Pulmonary vein

B. Coronary artery

Where are structures I, II and III found in the human body?

B. I are in the lungs, II are in the small intestines, III are in the kidneys

What is a characteristic of type II diabetes? A. Insufficient insulin B. Insulin insensitivity C. Excess glucagon D. Low white blood cell count

B. Insulin insensitivity

What causes the rate of heart contraction to increase or decrease? A. The heart muscle itself B. Nerve impulses from the brain C. A hormone from the thyroid gland D. The rate of return of blood to the left atrium

B. Nerve impulses from the brain

What is a feature of the human circulatory system? A. The wall of the right ventricle of the heart is the thickest of the four chambers. B. The pulmonary artery and vena cava both carry deoxygenated blood. C. Valves are found in arteries and veins but not capillaries. D. Epinephrine acts on the pacemaker to reduce heart rate.

B. The pulmonary artery and vena cava both carry deoxygenated blood.

What is a role of the coronary arteries? A. To supply information about blood temperature to the hypothalamus B. To supply the heart muscle with oxygen and nutrients C. To carry blood away from the heart D. To monitor blood pH

B. To supply the heart muscle with oxygen and nutrients

What processes occur during assimilation and absorption of lipids? A. lipids are broken down by enzymes, lipids are egested B. lipids are incorporated into new membranes, lipids pass into the lacteal C. lipids pass into the lacteal, lipids are incorporated into new membranes D. lipids are egested, lipids are broken down by enzymes

B. lipids are incorporated into new membranes, lipids pass into the lacteal

In which parts of the digestive system are most water and glucose absorbed?

B. water is absorbed in structure II and glucose is absorbed in structure III

How does the hypothalamus respond to a very high body temperature? A. Increases muscle contraction B. Stops receiving sensory input C. Causes dilation of skin arterioles D. Slows the heart rate

C. Causes dilation of skin arterioles

Glucose is absorbed through protein channels in the plasma membrane of epithelium cells in the small intestine. Which characteristics of glucose prevent its diffusion through the phospholipid bilayer? A. It is non-polar and therefore hydrophobic. B. Its hydrogen bonds link with amino acids in the protein channel. C. It is polar and therefore hydrophilic. D. Its covalent bonds interact with the phospholipids.

C. It is polar and therefore hydrophilic.

Which vessel carries deoxygenated blood from the heart to the lungs? A. Vena cava B. Coronary vein C. Pulmonary artery D. Pulmonary vein

C. Pulmonary artery

Where in the digestive system is the largest volume of water absorbed from? A. Colon B. Pancreas C. Small intestine D. Liver

C. Small intestine

Which of the following parts of the digestive system secrete proteases? A. Stomach B. Stomach, small intestine, large intestine C. Stomach and small intestine D. Large intestine

C. Stomach and small intestine

When the left ventricle is relaxed, what is the state of the valves?

C. The AV valve is open and the Semilunar valve is closed

What is a role of the coronary arteries? A. To transport oxygen from the lungs directly to the heart muscle B. To remove deoxygenated blood from the heart muscle C. To supply the heart muscle with nutrients D. To remove cholesterol from the heart muscle

C. To supply the heart muscle with nutrients

Enzymes produced by the pancreas could pass out of the body via the anus. Which route would these enzymes take to do this?

C. pancreas → small intestine → large intestine → anus

Is the blood in the aorta, left ventricle and pulmonary artery oxygenated or deoxygenated?

C. the aorta contains oxygenated blood, the left ventricle contains oxygenated blood, and the pulmonary artery contains deoxygenated blood

What is the condition of the valves of the heart when the right ventricle is contracting?

D. AV valves are closed and the semilunar valve is open

What is the state of the atrio-ventricular and semilunar valves when the left ventricle contracts?

D. AV valves are closed and the semilunar valve is open

What structures in the small intestine transport most fats? A. Collecting ducts B. Capillaries C. Veins D. Lacteals

D. Lacteals

What is a similarity between arteries and capillaries? A. They both have elastic tissue. B. They both have smooth muscle cells. C. Neither has collagen fibers in their walls. D. Neither has valves.

D. Neither has valves.

Which two hormones promote thickening of the endometrium? A. FSH and LH B. Estrogen and FSH C. LH and estrogen D. Progesterone and estrogen

D. Progesterone and estrogen

Which is a process occurring in the small intestine? A. fatty acids, lipase from the liver, glycerol B. nucleic acids, endopeptidase from the pancreas, nucleotides C. maltose, glucagon from a cells of the pancreas, glucose D. Starch, amylase from the pancreas, glucose

D. Substrate: Starch, Digesting enzyme: amylase from the pancreas, Final product absorbed: glucose

What role does the medulla of the brain have in controlling heart rate? A. To secrete adrenaline to speed up the heart. B. To stimulate myogenic heart muscle contraction. C. To block pacemaker activity. D. To adjust heart rate to changing blood pressure.

D. To adjust heart rate to changing blood pressure.

What is an important function of the lacteal in the villus? A. Secretion of mucus B. Secretion of enzymes C. Transport of glucose D. Transport of fats

D. Transport of fats

A structure has a thin epithelium of one cell layer and contains a lacteal and blood capillaries. It has protein channels and mitochondria to aid absorption. What is this structure? A. Alveolus B. Gastric gland C. Pancreas D. Villus

D. Villus

Outline the reason for one named substance found in food not being digested and absorbed by humans

Humans cannot digest cellulose because they lack the enzymes essential for breaking the beta-acetyl linkages to digest lignin.

Explain the need for enzymes in digestion

The rate of digestion at body temperature would be too slow and enzymes increase the rate of digestion. Enzymes break large molecules down into small/soluble molecules; for absorption and diffusion into blood.

Explain how the small intestine moves, digests and absorbs food

a. contraction of muscle layers/peristalsis helps move food. This muscle contraction prevents the backward movement of food and the contraction of longitudinal muscles moves food along the gut. b. peristalsis mixes food with intestinal enzymes c. These enzymes digest macromolecules into monomers d. pancreatic enzymes, such as amylase and lipase, chemically digests food in the lumen of the small intestine. e. Pancreatic amylase digests starch f. bile/bicarbonate secreted into the small intestine creates favorable pH for enzymes g. A final digestion into monomers is associated with epithelial cells of the small intestine h. mucosa layer/inside surface/lining of small intestine contains villi/finger-like projections i. villi/microvilli increase surface area for better absorption j. villi absorb products of digestion/monomers/mineral «ions»/vitamins k. glucose/amino acids enters capillaries l. absorption involves active transport/diffusion/facilitated diffusion m. different nutrients are absorbed by different transport mechanisms

Explain how the structure of a villus in the small intestine is related to its function [7 marks]

a. the villus has a large surface area to volume ratio where microvilli increase surface area for absorption b. the thin surface (epithelial) layer allow products of digestion to pass easily through c. channel proteins, located in the plasma membrane, are used for facilitated diffusion d. a network of capillaries inside each villus are used for movement of absorbed products e. capillaries transport absorbed nutrients/sugars and amino acids away from small intestine f. blood flow in capillaries maintains concentration gradient g. fatty acids move away from the small intestine h. a large number of mitochondria provide ATP needed for active transport i. protein pumps in membrane (of microvilli) carry out active transport j. pinocytosis occurs at surface (epithelial) layer

Compare gastric juice and pancreatic juice

gastric juices are produced by glands in the stomach wall while pancreatic juice is produced by the pancreas. Gastric juices are acidic with a low pH while pancreatic juices are alkaline with a high pH. gastric juices contain hydrochloric acid and contains mucus while pancreatic juices contains bicarbonate and no mucus

Explain how the increase in CO2 concentration affects the release of oxygen to respiring cells.

increased levels of CO2 lower the pH of the blood. This results in a decreased affinity of the hemoglobin for oxygen and a greater release of oxygen. This shifts the oxygen dissociation curve to the right/Bohr shift

What structures in the small intestine transport most fats?

lacteals

What sequence of organs do substances pass through, as they move through the human digestive system?

mouth, esophagus, stomach, small intestine, large intestine, anus