Osmoregulation And Excretion

Front 1

Osmoregulation

Back 1

Based on controlled movement of solutes between internal fluids and the external environment

Front 2

Osmosis

Back 2

Movement of water across a selectively permeable membrane

Front 3

Osmolarity

Back 3

Solute concentration of a solution, determines the direction of movement of water across the membrane

Front 4

Stenohaline

Back 4

Cannot tolerate substantial changes in external osmolarity

Front 5

Euryhaline

Back 5

Can survive large fluctuations in external osmolarity

Front 6

Anhydrobiosis

Back 6

Some aquatic invertebrates in temporary ponds lose almost all their body water and survive in a dormant state

Front 7

Transport epithelia

Back 7

Specialized epithelial cells that regulate solute movement

Front 8

Peritubular capillaries

Back 8

Surround the proximal and distal tubules, capillaries that deliver blood to the proximal tubules and distal tubule

Front 9

Vasa Recta

Back 9

Capillaries that serve the loop of Henle

Front 10

Juxtaglomerular apparatus

Back 10

Releases the enzyme renin (initiates reactions that increase blood pressure) when there is a drop in blood pressure near the glomerulus

Front 11

If two solutions differ in osmolarity, in which direction will water flow?

Back 11

Water will flow to the solution with the higher osmolarity, or higher concentration of solutes.

Front 12

What is the difference between an osmoconformer and an osmoregulator?

Back 12

An osmoconformer do not regulate their osmolarity; there is an equal movement of water between the animal and its environment. An osmoregulator uses energy to control the amount of water it gains and loses; there is an unequal movement of water between the animal and its environment.

Front 13

What is the mechanism utilized by marine birds that allows them to survive on seawater as their source of drinking water?

Back 13

Marine birds use transport epithelia arranged into nasal salt glands to remove excess sodium chloride from the blood in a countercurrent system.

Front 14

What is the relationship between the type of nitrogenous waste an animal produces and its environment?

Back 14

The nitrogenous waste an animal produces depends on the animal’s evolutionary history and habitat. For example, an aquatic animal may release ammonia across its entire body surface because it is surrounded by water. This is not the case for animals that don’t have access to large quantities or water, as ammonia is highly toxic and needs to be diluter before excretion.

Front 15

What is the advantage/disadvantage of producing uric acid as a waste product versus urea?

Back 15

Uric acid uses less water but more energy than urea. Urea uses less energy but more water than uric acid.

Front 16

What are the four basic steps common to excretory systems that produce urine?

Back 16

Filtration: Pressure-filtering of body fluid, non-selective
Reabsorption: Reclaiming valuable solutes and water
Secretion: Adding toxins and other solutes from the body fluids to the filtrate
Excretion: Elimination of the filtrate from the system

Front 17

What are the major organs of the human excretory system?

Back 17

Posterior Vena Cava: major associated blood vessel
Renal Artery and vein: major associated blood vessel
Kidney: Filters, cleanses, monitors pH, K, and NaCl of body and blood pressure
Ureter: Tubes that carry waste to bladder
Urinary Bladder: Holding tank of waste
Urethra: Smooth muscle under voluntary control that releases waste from bladder

Front 18

What is a nephron and what are its parts?

Back 18

Nephron: Functional unit of the vertebrate kidney consisting of a single long tubule as well as a ball of capillaries (glomerulus)
Proximal tubule
Loop of Henle
Distal tubule

Front 19

What are the two distinct regions of the mammalian kidney called, and which parts of the nephron are found in each?

Back 19

Renal cortex: Includes the cortical nephron and all of juxtamedullary nephron except for Loop of Henle
Renal medulla: Includes Loop of Henle of juxtamedullary nephrons

Front 20

What is the function of the glomerulus? Bowman’s capsule? afferent arteriole? efferent arteriole? proximal tubule? Loop of Henle? distal tubule? collecting duct?

Back 20

Glomerulus: Ball of capillaries surrounded by Bowman’s capsule, site of filtration
Bowman’s capsule: Receptacle where filtrate enters from the blood
Afferent arteriole: Supplies blood
Efferent arteriole: Takes away blood
Proximal tubule: Site of reabsorption, salt, water, nutrients transported actively and passively away
Loop of Henle: Functions in water and salt reabsorption
Descending loop: Reabsorption of water
Ascending loop: Reabsorption of salt
Distal Tubule: Regulates K+ and NaCl concentrations of body fluids
Collecting Duct: Carries filtrate to the renal pelvis, filtrate becomes more concentrated

Front 21

Filtration of small molecules in the kidney is said to be nonselective. Explain.

Back 21

Filtration filters all small molecules, whether they are salt, glucose, amino acids, vitamins, or nitrogenous wastes. It doesn’t matter if the molecule is “good” or “bad”.

Front 22

What is the difference between a cortical and juxtamedullary nephron?

Back 22

The cortical nephron is located in the renal cortex, while the juxtamedullary nephron is located in both the renal cortex and renal medulla. The juxtamedullary nephrons allow for the urine to be hyperosmotic (more concentrated) to the body.

Front 23

What are the two major contributors to the ability of the kidneys to concentrate urine?

Back 23

1. The precise arrangement of the loops of Henle and collecting ducts.
2. Active transport of NaCl out of the ascending limb of the loop of Henle.

Front 24

What term is used to describe a countercurrent system in which energy is expended to establish a concentration gradient?

Back 24

Countercurrent Multiplier System

Front 25

What is the role of ADH in water conservation by the kidney?

Back 25

ADH stands for Antidiuretic Hormone. This increases water reabsorption by increasing the number of water channels. More channels means more water collected.

Front 26

Describe how the renin-angiotensin-aldosterone system (RAAS) works to increase blood volume and pressure.

Back 26

The juxtaglomerular apparatus releases the enzyme renin, which activates angiotensinogen into its active form, angiotensin II. Angiotensin II constricts arterioles that flow to the kidneys, which raises blood pressure. They also stimulate the release of aldosterone from the adrenal glands, which increase absorption of Na+ and water, which leads to an increase in blood volume and pressure.

Front 27

What is the relationship between RAAS and atrial natriuretic peptide (ANP)?

Back 27

RAAS increases water reabsorption and responds to a decrease in blood volume. Atrial natriuretic peptide responds to an increase in blood volume and inhibits renin, inhibits NaCl reabsorption, and reduces aldosterone. ANP decreases blood volume.