Osmoregulation, Mammalian Urinary System, Gas Exchange and Circulation

A comprehensive set of flashcards covering osmoregulation, mammalian urinary system, gas exchange, and circulation for exam preparation.

What are osmoregulators?

Osmoregulators are organisms that maintain set points for internal fluid levels and solute concentrations.

What do osmoregulators do?

They regulate internal concentrations of solutes and water, which is essential for homeostasis.

What is the difference between osmoregulators and osmoconformers?

Osmoconformers do not regulate internal concentrations; they match their environment, while osmoregulators actively maintain set points.

What adaptation do terrestrial insects use for water conservation?

Terrestrial insects have an exoskeleton with a cuticle made of chitin, protein, and wax.

What are Malpighian tubules?

Malpighian tubules are structures in insects that form filtrate from hemolymph and aid in excretion.

What is the role of Malpighian tubules in osmoregulation?

They actively transport electrolytes and water, allowing for reabsorption depending on hydration levels.

What is the basic structure of the mammalian urinary system?

The mammalian urinary system consists of kidneys, ureters, bladder, and urethra.

What are the major functions of the nephron?

Filtration, reabsorption, and secretion of substances are the primary functions.

What happens during the filtration process in the nephron?

Fluid and solutes leave the glomerulus and enter Bowman’s capsule as filtrate.

What is reabsorption in the nephron?

Reabsorption is the process where solutes leave the filtrate and enter the peritubular capillaries.

What controls urine concentration?

The presence of Antidiuretic Hormone (ADH) determines whether urine is concentrated or dilute.

What can cause concentrated urine formation?

The osmotic gradient and the action of ADH contribute to concentrated urine formation.

How does aldosterone influence urine formation?

Aldosterone increases Na/K pump activity in the DCT, promoting water reabsorption.

What is the role of tracheal systems in insects?

Tracheal systems enable direct air diffusion to tissues, allowing for gas exchange.

Why are gills effective for gas exchange?

Gills use a countercurrent flow mechanism, allowing for efficient oxygen extraction from water.

What is the pathway of airflow through the human respiratory system?

Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli.

How do pulmonary and systemic circulation differ?

Pulmonary circulation carries oxygen-poor blood to the lungs, while systemic circulation delivers oxygen-rich blood to the body.

What is the significance of the sinoatrial (SA) node?

The SA node establishes the baseline for heart rate and initiates contraction of the heart.

What does an electrocardiogram (ECG) measure?

An ECG records the electrical activity of the heart during contraction.

What is the cardiac cycle?

The cardiac cycle encompasses the systole and diastole of both the atria and ventricles.

What does stroke volume (SV) refer to in cardiac output?

SV is the volume of blood ejected from the left ventricle during ventricular systole.

How is blood pressure measured?

Blood pressure is measured as systolic over diastolic pressure (e.g., 120/80).

What influences blood pressure (BP)?

Cardiac output, vascular resistance, blood volume, viscosity, vessel diameter, and length affect BP.

What are the formed elements of blood?

The formed elements include red blood cells, white blood cells, and platelets suspended in plasma.

What is erythropoiesis?

Erythropoiesis is the formation of red blood cells in the bone marrow.

What function do leukocytes serve in blood?

Leukocytes defend the body against invading microorganisms.

How do platelets function in hemostasis?

Platelets form clots to prevent bleeding by plugging holes in vessel walls.

What is the role of the aorta in the circulatory system?

The aorta distributes oxygen-rich blood from the heart to the body.

What differentiates open and closed circulatory systems?

Open systems have hemolymph in direct contact with tissues, while closed systems contain blood in vessels.

What are capillaries primarily involved in?

Capillaries facilitate the exchange of gases and nutrients between blood and tissues.

What is the function of precapillary sphincters?

Precapillary sphincters regulate blood flow into capillary beds.

How does the structure of veins differ from arteries?

Veins have thinner walls, larger lumens, and valves to support blood flow back to the heart.

What is the function of the renal corpuscle?

The renal corpuscle is where blood filtration occurs, consisting of the glomerulus and Bowman’s capsule.

What effect does the descending limb of the Loop of Henle have?

The descending limb allows water reabsorption, concentrating the filtrate.

What does the thick ascending limb of the Loop of Henle do?

It actively transports Na+ and Cl- out of the filtrate, making it hypotonic.

What components are found in plasma?

Plasma consists of water, solutes, and proteins like albumin and globulins.

What is the normal blood pH range?

The normal blood pH range is 7.35 to 7.45.

What is the role of baroreceptors in blood pressure regulation?

Baroreceptors detect stretch from blood pressure and relay impulses to the cardiovascular center.

What happens during diastole in the heart?

During diastole, the heart relaxes and fills with blood.

What are the two types of blood circulation associated with the heart?

Pulmonary circulation and systemic circulation.

What is the pathway of blood flow during pulmonary circulation?

Blood flows from the right ventricle to the lungs and back to the left atrium.

What are the two major functions of the heart valves?

To prevent backflow of blood and ensure proper blood flow direction.

What is the significance of the cardiac output?

Cardiac output is the total volume of blood the heart pumps per minute.