3.7 Excetory System

7/31/2019 3.7 Excetory System

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IB Biology Review

Excretory System


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Definitions

ExcretionThe disposal of nitrogen-containing waste products ofmetabolism

Osmoregulation

How organisms regulate solute concentrations and balancethe gain and loss of water


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Why is excretion important?

Body needs to get rid of waste

Otherwise, waste will build up

Take up space

Prevent metabolic processesPoison organism


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What are the two types ofwaste produced by the body?

Solid waste

Liquid waste (urea)

Where is solid waste processed?Large intestine

Where is solid waste excreted?

Rectum and anusWhere is liquid waste processed?

Kidney

Where is liquid waste excreted?

Urinary tract


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Excretory System Overview

You do not need to know this, just adding the visual


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Overview of Excretory System,Kidney, and Nephron Structure


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Kidney Structure

Be able to draw: cortex, medulla with pyramids,pelvis, ureter, renal artery, and renal vein


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Identify the components of a kidney.

cortex

medulla

renal pyramids

pelvis

ureter

renal artery

renal vein


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Nephron Structure

Be able to draw a nephron

Must include

glomerulus

Bowman's capsuleproximal convoluted tubule

loop of Henleascending and descending

both labeleddistal convoluted tubule

collecting duct

Ascendingportion ofLoop of Henle

Descendingportion ofLoop of Henle


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Identify the components of a nephron.

glomerulus

Bowman's capsule

proximal convolutedtubule

loop of Henle

ascending and descending

portions of the Loop/Henle

distal convoluted tubule

collecting duct

Ascendingportion ofLoop of Henle

Descendingportion ofLoop of Henle


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How do solutes and water get into theproximal convoluted tubule?

High pressure inarteries/arterioles leadinginto the nephron

This leads to ultrafiltration

in the capillaries of theglomerulus

Water and solutes such asurea, glucose, salts, andamino acids drain into theBowman's capsule

Water and solutes dumpedinto the proximalconvoluted tubule


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How are salt, amino acids, and water reabsorbedinto blood from the proximal convoluted tubule?

Salt (NaCl), glucose, andamino acids aretransported back to the

blood by active transport

Water follows in to theblood by osmosis


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Solute Reabsorption Diagram

H th ll th ll f th


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How are the cells on the wall of theproximal convoluted tubule specially

adapted for selective absorption?

microvilli increase the surface area for absorptionthrough active transport

mitochondria produce ATP for active transport


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What happens after filtration and reabsorption?

3. Secretion

Toxins, excess ions andother substances areactively transported out ofthe filtrate

4. ExcretionThe filtrate is sent out ofthe nephron and out of the

body as urine


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What are some reasons an individualsblood solute concentration increase?

vomiting and diarrhea makes the body lose water

increased salt intake (from eating those potato chips...)

drinking alcohol adds ethanol and sugar

drinking coffee adds sugar and caffeine

excess sweating makes the body lose water

if the individual isnt drinking enough water


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Anti-Diuretic Hormone (ADH) Function

Osmo-receptors in the brainmonitor blood solute concentration

It is a hormone that is synthesizedin the brain (hypothalamus)

When solute concentrations arehigh, ADH is released into the

blood stream

ADH travels to the nephrons of the

kidney and tell kidney to reabsorbmore water

This is a negative feedback controlof ADH secretion

IB E Q ti


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1. Blood vessels carry blood to and from the kidney.Draw a labelled diagram to show the internal structureof the kidney, including the vessels that are connected

to it. (5 marks)cortex shown at the edge of kidney;

medulla shown inside the cortex (with pyramids);

pelvis shown on the concave side of the kidney;

ureter shown connecting with the pelvis

renal artery shown connected

renal vein shown connected

IB Exam Question

IB E Q ti


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2. Draw a labelled diagram of a nephron.(6 marks)

glomerulus;

Bowman's capsule;

proximal convoluted tubule;loop of Henle;

ascending and descending both labeled;

distal convoluted tubule;

collecting duct;

IB Exam Question

IB E a Que tio


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3. Which part of the nephron shown belowis impermeable to water molecules? (1 mark)

A. I

B. II

C. IIID. IV

Correct answer: C

IB Exam Question

IB Exam Question


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4. Describe how the liquid and solutes that flow through

the proximal convoluted tubule are produced. (2 marks)

high pressure in arteries/arterioles leading into thenephron;

this leads to ultrafiltration in the capillaries of the

glomerulus;Water and solutes such as urea, glucose, salts, andamino acids drain into the Bowman's capsule which

leads to the proximal convoluted tubule;

IB Exam Question

IB Exam Question


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5. Explain how the structure of the proximal convoluted tubule

cell is adapted to carry out selective re-absorption. (2 marks)

microvilli increase the surface area for absorption /active transport;

mitochondria produce ATP for active transport;

IB Exam Question

IB Exam Question


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6. Name three solutes that are selectively reabsorbedback into the blood in the proximal convoluted tubule.

(1 mark)glucose

amino acids

salt (NaCl)

7. Describe how these solutes and water are reabsorbed

by the blood from the proximal convoluted tubule.

Salt (NaCl), glucose, and amino acids are transportedback to the blood by active transport

Water follows in to the blood by osmosis

IB Exam Question

IB Exam Question


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8. Where in the kidney does ultrafiltrationtake place? (1 mark)

A. Glomerulus

B. Loop of Henl

C. Proximal tubuleD. Collecting ducts

Correct answer: A

IB Exam Question

IB Exam Question


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9. What can be changed in the kidney over a period of timein order to carry out the process of osmoregulation?(1 mark)

A. The amount of blood flowing to the kidney

B. The amount of fluid filtered from the blood in theglomeruli

C. The amount of solutes selectively reabsorbed inthe proximal convoluted tubule

D. The amount of water reabsorbed in the collecting

ducts

Correct answer: D

IB Exam Question

IB Exam Question


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10. State three reasons why a persons bloodplasma solute concentration may increase.

(3 marks)

vomiting / diarrhoea

increase salt intake;

drink alcohol / coffee;excess sweating / lack of water intake;

IB Exam Question

IB Exam Question


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11. How does anti-diuretic hormone(ADH) function in osmoregulation.

It is a hormone that is synthesized in the brain(hypothalamus)

Osmo-receptors in the brain monitor blood soluteconcentration.

When solute concentrations are high, ADH is releasedinto the blood stream

The hormone travels to the nephrons of the kidneyand signal kidney to reabsorb more water.,

This is a negative feedback control of ADH secretion;

IB Exam Question

IB Exam Question


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12. Anti-diuretic hormone has its main effect

on which part of the nephron? (1 mark)

A. Proximal tubule

B. Bowmans capsule

C. Loop of HenleD. Collecting duct

Correct answer: D

IB Exam Question

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3.7 Excetory System