Water balance and excretory system

Question 1

Water Balance

Answer 1

The body’s internal environment of extracellular fluid must maintain a constant volume and solute content
affects ionic concentration, concentration of metabolites, and pH

Water regulation is simple:
Increased water intake = increased urine output
Increase in exercise or decreased water input = reduced urine output

These adjustments involve the interaction of the body’s two communication systems: the nervous system and the endocrine system

Question 2

Osmosis

Answer 2

Osmosis is the movement of water particles from a hypotonic solution to a hypertonic solution

Osmotic pressure results from the difference in solute concentration between the two sides of a selectively permeable membrane

hypotonic -> hypertonic

Question 3

Osmoregulation

Answer 3

The important factor for concentration is osmosis is the number of particles in a given volume of solution, not the number of molecules

Osmoregulation is the process of actively regulating the osmotic pressure of bodily fluids and cells (isoosmotic)

The concentration of solutes will affect the osmosis of water of cells and extracellular fluids

Question 4

Excretion

Answer 4

Energy is obtained by cells by converting complex organic compounds into simpler compounds
many of these simpler compounds can be harmful

To maintain life processes, the body must eliminate waste products
- the lungs eliminate CO2 from cellular respiration
- the large intestines remove toxic wastes from the digestive system
- the liver transforms ingested toxins, such as alcohol and heavy metals, into soluble compounds that can be eliminated by the kidneys
- the liver also transforms the hazardous products of protein metabolism into metabolites, which are then eliminated by the kidneys

Question 5

Deamination

Answer 5

Deamination is the process in which the amino group from amino acids is removed (and broken into metabolites) and discarded

Removal of amino group (-NH2) from organic compounds must be discarded

Deamination produces ammonia (NH3), a highly toxic water-soluble gas

Deamination occurs in the liver

Ammonia is produced

In the liver, ammonia is combined with carbon dioxide to form urea

Kidneys will filter the water and urea

Question 6

Water Balance:

Answer 6

Kidneys
Hormones: ADH (short term response), Aldosterone (long term response)

ADH: Anti-diuretic hormone

Question 7

Signs of dehydration

Answer 7

• Lack of urination and sweating
• dry mouth
• dark urine

Question 8

ADH

Answer 8

controls the reabsorption of water in the kidneys

water poisoning: solute can’t get to cells bc your water levels are thrown off so much

Question 9

The Excretory System

Answer 9

The excretory system aids the body in fluid and water regulation and expelling waste

This important for the organism so it can retain water and remove harmful waste so it does not build up

Question 10

Kidneys function

Answer 10

Kidneys function to filter the waste from blood and maintaining water balance

Humans deplete their water reserves faster than their food reserves

The average adult loses about 2 L of water every day through urine, perspiration, and exhaled air

Question 11

Six Functions of the Kidneys

Answer 11

Regulation of blood water levels
Reabsorption of useful substances into the blood
Adjustments of the levels of salts and ions in the blood
Excretion of urea and other metabolic wastes
Homeostatic regulation of pH
Production of hormones

Question 12

Cross Section of the Kidney

Answer 12

Three areas are discerned:

Cortex
Outer layer of connective tissue all around the kidney
Medulla
Inner layer beneath the cortex
Renal Pelvis
Hollow chamber in the middle of the kidney that joins the kidney with the ureter

Question 13

Blood: In and Out of the Nephrons

Answer 13

Afferent arterioles
Small branches from the renal artery that supply the nephrons with blood
They branch into a capillary bed called the…
Glomerulus
High-pressure capillary bed that is the site of filtration
Efferent arterioles
Blood leaves the glomerulus by way of these efferent arterioles
Blood is carried from the efferent arterioles to a net of capillaries called…
Peritubular capillaries (also called vasa recta)
These capillaries wrap around the kidney tubules
They lead to venules that lead the blood out of the kidney through the renal vein

afferent → branch into capillary networks
glomerulus → under VERY high pressure
it is forcing substances out of capillaries
F off – travelling away (eFF)

Glomerulus is the site of filtration

Question 14

Filtrate movement

Answer 14

High blood pressure at the glomerulus forces filtrate (water and small molecules) to be filtered into the…
Bowman’s capsule
fluids to be processed into urine enter the Bowman’s capsule from the blood
the Bowman’s capsule tapers to a thin tubule called the …
proximal tubule
carries the urine to the…
loop of Henle
a thin tube that descends into the medulla of the kidney and then starts ascending back up and leading the urine into the…
distal tubule
carries the urine to the…
collecting ducts
this tube collects urine from many nephrons that, in turn, merge in the pelvis of the kidney (these are the last segments of the nephrons)

Question 15

Formation of Urine and Osmoregulation

Answer 15

Urine formation and the maintenance of a water and solute balance depend of three functions:

Filtration Glomerulus
the process by which blood or body fluids pass through a selectively permeable membrane
accomplished by the movement of fluids from the blood into the Bowman’s capsule
Reabsorption
involves the transfer of essential solutes and water from the nephron back into the blood
Secretion
involves the movement of materials from the blood back into the nephron