Final Review Unit 3

Choose the correct statement from the list below about fatty acids

Free fatty acid absorption occurs in the small intestine.

What type of macronutrient is chemically digested in the oral cavity, and what enzyme is primarily responsible?

Starches (carbohydrates)- amylase

Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?

The large decrease in blood pressure as blood moves through the lungs may prevent efficient circulation through the rest of the body.

The smallest airway through which inspired air passes before gas exchange occurs in the mammalian lungs is the _____.

bronchiole

The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.

calcium

From the pulmonary veins, blood flows to the _____.

left atrium

From the superior vena cava, blood flows to the _____.

right atrium

During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.

the myosin head

Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.

thin filaments

Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber? 1. Tropomyosin shifts and unblocks the cross-bridge binding sites. 2. Calcium is released and binds to the troponin complex. 3. Transverse tubules depolarize the sarcoplasmic reticulum. 4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP. 5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.

5 → 3 → 2 → 1 → 4

Briefly explain/describe the role of adenosine triphosphate (ATP) as it relates to muscle contraction. What protein does ATP interact with during muscle contraction, and what are the three sources for replenishment of ATP (i.e., phosphorylation of ADP)?

ATP drives the formation of cross bridges between the thick and thin filaments. When ATP is hydrolyzed the myosin head is in a high energy state and a crossbridge is able to form. The formation releases ADP and Phosphate and myosin is returned to a low energy state. ATP is replenished by creatine phosphate, glycolysis and aerobic respiration.

Which lung structure is a tiny sac that functions as an interface between air and blood?

Alveolus.

Which of the following best describes an artery?

Arteries carry blood away from the heart.

Briefly describe the change in total cross-sectional area of blood vessels as blood flows away from the heart through arteries, capillaries, and then returns through veins. How does this affect blood flow velocity?

As blood flows away from the heart, the cross- sectional diameter gets larger from arteries → arterioles → capillaries. Because the cross- sectional area is larger, the velocity slows so there is more time for gas exchange. As it comes back, the diameter gets smaller, increasing velocity again

_____ is secreted by the _____ and acts to emulsify _____ in the _____.

Bile ... liver ... fats ... small intestine

Choose the correct statement from the list below about carbohydrates

Carbohydrate digestion begins in the mouth with salivary amylase.

For each major class of macronutrient, what are the end products of chemical digestion that are absorbed across the lining of the small intestine and transported into either the blood or lymph?

Carbohydrates → monosaccharides, proteins → amino acids, nucleic acids → nitrogen bases, sugars, phosphates , fats → glycerol, fatty acids, monoglycerides

CO2 in gas exchange

Carbon dioxide diffuses from body tissues to blood. Carbon dioxide is transported either in the plasma, bound to hemoglobin, or in the form of bicarbonate. In the lungs, carbon dioxide diffuses from the capillaries into the alveoli. When you exhale, carbon dioxide leaves the body.

inhalation and exhalation

During inhalation, the diaphragm and rib muscles contract, increasing the volume of the lungs. Air enters the nose or mouth and flows down the trachea, bronchi, and bronchioles, and into the alveoli. During exhalation, the diaphragm and rib muscles relax, decreasing the volume of the lungs. Air leaves the alveoli and flows up the bronchioles, bronchi, and trachea, and exits through the nose or mouth.

List the major structures (blood vessels, valves, capillaries of the lungs, and chambers of the heart) through which a drop of blood will travel, beginning with the vena cavae and ending with the aorta.

Enter in vena cava → RA → R AV valve → RV → R semilunar valve → pulmonary artery → lungs → pulmonary veins → LA → L AV valve → LV → L semilunar valve → aorta

The pancreas is involved in the digestion of _____. I) protein II) fat III) nucleic acids IV) carbohydrates

I, II, III, and IV

Which statement regarding the mammalian heart is correct?

In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs.

What specific structures are involved in formation of a cross-bridge in a sarcomere? Be very specific about what is connecting to what.

Myosin head (thick filament) binds to actin filaments forming cross bridges at myosin binding sites

Strategies for long dives among marine mammals can roughly be divided into two categories: increased O2 storage and O2 conservation. Briefly describe the mechanisms for both categories. What additional adaptation is common among diving mammals?

O2 storage: high blood to body volume ratio, O2 stored as myoglobin. O2 conservation: decrease buoyancy during passive descent and decreased blood flow to nonessential areas. Utilize fermentation for ATP production in muscles when O2 is depleted.

oxygen in gas exchange

Oxygen diffuses from the alveoli to capillaries in the lungs. Almost all the oxygen in the blood is bound to hemoglobin. Oxygen is carried all over the body and diffuses from blood to body tissues.

What component(s) of pancreatic juice are involved in the chemical digestion of carbohydrates? Of proteins? Of nucleic acids? Of triglycerides?

Pancreatic amylase continues breakdown of carbohydrates. Trypsin and chymotrypsin break down polypeptides, carboxypeptidase removes last AA found at carboxyl end. Pancreatic nucleases break down nucleic acids. pancreatic lipase breaks down lipids and fats

How does the cooperativity of hemoglobin contribute to its function in gas exchange?

Positive feedback loop- if one subunit binds to O2 it increases the affinity for the next subunit to bind.

Which statement about human blood vessels is correct?

Pulmonary veins carry oxygen-rich blood to the heart.

Which of the following statements comparing respiration in fish and in mammals is correct?

The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.

Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulatory network contribute to reducing blood pressure to avoid this scenario?

The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.

Briefly explain/describe the role of the troponin complex as it relates to initiation of a muscle contraction. In other words, what does troponin do when it's activated and how is it activated?

The troponin complex anchors the tropomyosin. Calcium binds to the troponin complex, causing the troponin complex to change shape so the myosin binding sites are not blocked and a cross bridge can be formed.

detailed narrative of the events occurring at a neuromuscular junction

The voltage gated calcium channels to open causing an influx of Ca2+. Then there is exocytosis of the Ach; Ach binds to ligand gated Na+ channels on sarcolemma. Then there is influx of Na+ → AP → T tubules → sarcoplasmic reticulum. Voltage gated Ca2+ , increase intracellular calcium, Ca2+ binds to troponin complex. Troponin complex changes tertiary structure, pulls tropomyosin off myosin binding sites → cross bridges. Binding, hydrolysis and dissociation of ATP → myosin head binds and forms cross bridge → pulls thin filament, releases when new ATP binds. SR actively removes Ca2+ from cytosol

What is the importance of the mucins that are released by salivary glands?

They are glycoproteins that make food slippery enough to slide easily through the esophagus.

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.

The bile salts _____.

emulsify fats in the duodenum

True or false? The pressure inside the human chest cavity is always positive, so the lungs stay relatively inflated even upon exhalation.

false

To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation, an organism would need a(n) _____.

four-chambered heart

From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.

inferior vena cava

The contraction of skeletal muscles is based on _____.

myosin cross-bridges binding to actin and transitioning from a high-energy to a low-energy state

Blood returns to the heart via the _____.

pulmonary veins

Which of the following organs is correctly paired with its function?

stomach - protein digestion

Which of the following develops the greatest pressure on the blood in the mammalian aorta?

systole of the left ventricle

Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____.

the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum

The velocity of blood flow is the lowest in capillaries because _____.

the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system

A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through _____.

two capillary beds

Which of the following is the correct sequence of blood flow in birds and mammals?

vena cava → right atrium → right ventricle pulmonary artery