Regulation of water content - Dynbio662.dyndns.info/DSE/WS/ws_E1_ch1_e.pdf1 Nephrons 2 cortex 3 medulla 4 pelvis 5 nephron 6 glomerulus 7 Bowman’s capsule 8 proximal convoluted tubule

Class: Name: ( ) Date:

New Senior Secondary Mastering Biology Oxford University Press 2015 (Second Edition)

- E1-1 -

E1

1 Regulation of water content

1.1 Importance of osmoregulation (Book E1, p. 3)

� If there is an imbalance between water intake and water loss, the (1) _______________

content of the blood and hence the (2) _______________ _______________ of the tissue

fluid that surrounds body cells will change. Water will therefore enter or leave the cells by

(3) _______________. If too much water is gained or lost, the cells will not function properly

and may even die.

� The maintenance of a stable water potential of body fluid in an organism is known as

(4) _______________ (滲透調節). The (5) _______________ (腎) of the (6) _______________

_______________ (泌尿系統) play an important part in this regulatory function.

1.2 The general plan of the urinary system (Book E1, p. 5)

(1) _______________

▲ The human urinary system (structures in brackets do not belong to the urinary system)

(dorsal aorta)

(posterior vena cava)

(renal artery (腎動脈))

(renal vein (腎靜脈))

(3) _______________

_______________ (膀胱)

two rings of

(4) _______________

_______________ (括約肌)

(5) _______________ (尿道)

female male

(2) _______________ (輸尿管)

(penis)

Key: �/� blood flow


- E1-2 -

Structure Feature and / or function

Kidney

� Surrounded by fat which protects the kidneys from (6) _______________

_______________

� Supplied with blood from the (7) _______________ _______________ and

drained by the (8) _______________ _______________

� Responsible for osmoregulation and (9) _______________

Ureter � Carries (10) _______________ produced by the kidneys to the urinary bladder

Urinary

bladder

� (11) _______________ urine temporarily

� Two rings of sphincter muscles (normally (12) _______________ (contracted /

relaxed) are present to control the (13) _______________ of urine from the

urinary bladder to the urethra

Urethra � Carries urine from the urinary bladder to the outside

� Go to

Practical 1.1 Examination of the mammalian urinary system

(Book E1, p. 113)

1.3 Structure of the kidney (Book E1, p. 7)

� (1) _______________ (腎元) are the functional units of the kidney.

(2) _______________

(皮層)

(3) _______________

(髓)

(4) _______________

(腎盂)

renal artery

renal vein

ureter

(5) _______________

branch

from renal artery

branch

from renal vein

▲ Position of nephrons in the kidney


- E1-3 -

� A nephron is made up of a (6) _______________ (腎小球), a (7) _______________

_______________ (鮑曼氏囊) and a long tubule. The tubule can be divided into several

sections.

1 First the tubule coils up in the cortex to form the (8) _______________ _______________

_______________ (近曲小管).

2 It then extends into the medulla to form the U-shaped (9) ______________ ____________

_______________ (亨利氏套).

3 It returns to the cortex and coils up again to form the (10) _____________ _____________

_______________ (遠曲小管).

� The distal convoluted tubule finally leads to the (11) ______________ ______________ (集尿管).

� Match parts I to VI of a nephron with their names.

glomerulus:

(12) ________

Bowman’s capsule:

(13) ________

proximal convoluted tubule:

(14) ________

loop of Henle:

(15) ________

distal convoluted tubule:

(16) ________

collecting duct:

(17) ________

� Go to

Practical 1.2 Examination of the mammalian kidney

(Book E1, p. 116)

▲ A nephron and its associated blood vessels

cortex

medulla

(from another nephron)

afferent arteriole (輸入小動脈)

efferent arteriole (輸出小動脈)

capillary

I

II

branch from renal artery

branch from renal vein

III

IV

V

VI

Key: � blood flow � flow of urine


- E1-4 -

1.4 Formation of urine (Book E1, p. 10)

� (1) _______________ (超濾) and (2) _______________ (重吸收) are two main processes

involved in urine formation.

1 Ultrafiltration

� When the blood reaches the glomerulus, it is maintained at a relatively (3) _______________

(high / low) pressure.

� The high blood pressure forces (4) _______________ and small (5) _______________

(soluble / insoluble) molecules (e.g. glucose, amino acids, salts and urea) in the plasma through

the thin walls of the (6) _______________ and the (7) _______________ _______________

into the capsular space. This process is called ultrafiltration. It is a (8) _______________

(active / passive) process.

� The glomerular filtrate has a similar composition to (12) _______________. However, no

(13) _______________ _______________ and (14) _______________ _______________ are

found in the glomerular filtrate because they are too (15) _______________ to pass through

the walls of the glomerulus and the Bowman’s capsule.

(10) _______________ arteriole

(9) _______________ arteriole

glomerulus

Bowman’s capsule blood flow

glucose

amino acids

water

salts

urea

capsular space (with

(11) _______________

_______________ (腎小球濾液))

▲ Ultrafiltration in the glomerulus and the Bowman’s capsule

to proximal convoluted tubule


- E1-5 -

2 Reabsorption

� After ultrafiltration, the glomerular filtrate flows through the kidney tubule. Meanwhile,

(16) _______________ substances (e.g. glucose and amino acids) and most of the

(17) _______________ in the filtrate are absorbed back into the surrounding capillaries. This

process is called reabsorption.

� Reabsorption occurs mainly in the (18) _______________ ______________ ______________.

� Adaptive features of the proximal convoluted tubule for reabsorption:

Feature Adaptation to reabsorption

It is long and highly

(19) _______________.

Increases the (20) _______________ _______________ and

the time for reabsorption

It is only one-cell thick. Shortens the (21) _______________ for reabsorption

The epithelial cells have many

(22) _______________.

Greatly increases the (23) _______________

_______________ for reabsorption

The epithelial cells contain many

(24) _______________.

Provides cells with a lot of (25) _______________ to enable

(26) _______________ _______________ of substances

Surrounded by a dense

(27) _______________ network

The blood allows the rapid transport of substances away

from the site of reabsorption, thus helping maintain a steep

(28) _______________ _______________ of substances

between the blood and the filtrate for efficient reabsorption

glomerulus

Bowman’s capsule

from renal artery

proximal convoluted tubule

distal convoluted tubule

to renal vein

collecting duct

capillary

loop of Henle

glomerular filtrate epithelial cells

of proximal

convoluted tubule

capillary

glucose,

amino acids and salt

water

urea Process(es) by which substances are reabsorbed

(d = diffusion; o = osmosis; a = active transport):

(29) _______________

(30) _______________

(31) _______________

Key: � blood flow � flow of urine


- E1-6 -

� The reabsorption of specific substances in different parts of the kidney tubule:

Part of the kidney tubule where reabsorption occurs

Substance absorbed (% reabsorbed)

Process Proximal convoluted

tubule

Loop of Henle

Distal convoluted

tubule

Collecting duct

(32) _______________

(100%)

Diffusion,

active

transport

�

(33) _______________

(100%)

Diffusion,

active

transport

�

(34) _______________

(80%)

Diffusion,

active

transport

� � � �

(35) _______________

(99%) Osmosis � � � �

(36) _______________

(50%) Diffusion � � � �

� After reabsorption, the remaining filtrate in the collecting duct is called (37) _______________,

which contains mostly water with salts, (38) _______________ and other metabolic waste.

1.5 The role of kidneys (Book E1, p. 17)

A Osmoregulation (Book E1, p. 17)

� A stable water potential of body fluid is mainly achieved by regulating the amount of

(1) _______________ reabsorbed from the glomerular filtrate in the kidney tubules.

� The amount of water reabsorbed in the kidney tubules is controlled by the

(2) _______________ _______________ (ADH) (抗利尿激素) released from the

(3) _______________ _______________ (垂體).

� ADH increases the (4) _______________ of the collecting duct to water so that a

(5) _______________ (greater / smaller) proportion of water is reabsorbed from the filtrate.

As a result, the volume of urine production is (6) _______________ (increased / decreased)

and more water is retained in the body.

� The release of ADH is controlled by the (7) _______________ (下丘腦) in the brain. The

hypothalamus contains (8) _______________ which can detect the water potential of the blood.


- E1-7 -

� How osmoregulation is carried out when the water potential of the blood becomes higher or

lower than normal:

B Excretion (Book E1, p. 19)

� Excretion is the elimination of (19) _______________ _______________ from the body.

� Metabolic waste (e.g. urea) is constantly produced and a high concentration of it is toxic to the

body. The kidneys remove metabolic waste from the blood by forming urine.

1.6 The dialysis machine (Book E1, p. 21)

� Patients with (1) _______________ _______________ (腎衰竭) cannot regulate the water

content of the body or remove metabolic waste from the blood effectively.

� They can be treated with (2) _______________ (血液透析) by using a (3) _______________

_______________ (透析機) (or a kidney machine (洗腎機)).

water potential of blood higher than normal

(e.g. after drinking a large amount of water)

water potential of blood lower than normal

(e.g. taking in little water or heavy sweating)

detected by osmoreceptors in hypothalamus detected by osmoreceptors in hypothalamus

the pituitary gland releases

(9) _______________ (less / more) ADH

wall of collecting duct becomes

(10) _______________ (less / more)

permeable to water

a (11) _______________ (greater /

smaller) proportion of water reabsorbed;

a (12) _______________ (larger / smaller)

volume of (13) _______________ (dilute /

concentrated) urine formed

normal water potential of blood

the pituitary gland releases

(14) _______________ (less / more) ADH

wall of collecting duct becomes

(15) _______________ (less / more)

permeable to water

a (16) _______________ (greater /

smaller) proportion of water reabsorbed;

a (17) _______________ (larger / smaller)

volume of (18) _______________ (dilute /

concentrated) urine formed

negative feedback

negative feedback


- E1-8 -

� Features of the two parts of a dialysis machine and their significance:

Feature Significance

Dialysis tubing

It is (4) _______________ permeable.

It only allows small molecules like urea

to pass through.

Helps remove (5) _______________

from the blood while retaining large

blood components like plasma

proteins and blood cells in the body

Has a water potential similar to that of

blood.

Prevents loss of (6) ______________

from the blood

The concentrations of nutrients (e.g.

glucose and amino acids) in it are

similar to that of blood.

Prevents loss of (7) ______________

from the blood Dialysing fluid

(透析液)

(8) ____________________ (Contains /

Does not contain) metabolic waste.

Allows metabolic waste in the blood

to diffuse into the dialysing fluid

▲ How a dialysis machine works

constant

temp.

bath

fresh

dialysing

fluid

used

dialysing

fluid

dialysing fluid

dialysis tubing

pump

1 Blood is pumped out of the patient’s body.

2 Metabolic waste

like urea diffuses

from the blood to

the dialysing fluid

along the

concentration gradient.

4 Plasma proteins

and blood cells are

retained in the blood

as they are too large

to pass through the tubing.

5 ‘Cleaned’

blood

returns to

the patient’s body.

dialysing fluid

dialysing fluid

blood

dialysis tubing Key: � blood flow

� flow of dialysing fluid

3 Nutrients are retained in the

blood (no net movement of

nutrients) as their concentrations

in dialysing fluid are similar to those in blood.


- E1-9 -

Answers

E1 Ch 1 Regulation of water content

1.1 1 water 2 water potential 3 osmosis 4 osmoregulation 5 kidneys

6 urinary system

1.2 1 kidneys 2 ureters 3 urinary bladder 4 sphincter muscles 5 urethra

6 mechanical shock 7 renal arteries 8 renal veins 9 excretion 10 urine

11 Stores 12 contracted 13 release

1.3 1 Nephrons 2 cortex 3 medulla 4 pelvis 5 nephron

6 glomerulus 7 Bowman’s capsule 8 proximal convoluted tubule 9 loop of Henle

10 distal convoluted tubule 11 collecting duct 12 I 13 II

14 IV 15 III 16 V 17 VI

1.4 1 Ultrafiltration 2 reabsorption 3 high 4 water 5 soluble

6 glomerulus 7 Bowman’s capsule 8 passive 9 afferent 10 efferent

11 glomerular filtrate 12 plasma 13 plasma proteins / blood cells

14 blood cells / plasma proteins 15 large 16 useful 17 water

18 proximal convoluted tubule 19 coiled 20 surface area 21 distance

22 microvilli 23 surface area 24 mitochondria 25 energy 26 active transport

27 capillary 28 concentration gradient 29 d & a 30 o

31 d 32 Glucose / Amino acid 33 Amino acid / Glucose

34 Salt 35 Water 36 Urea 37 urine 38 urea

1.5 1 water 2 antidiuretic hormone 3 pituitary gland 4 permeability

5 greater 6 decreased 7 hypothalamus 8 osmoreceptors 9 less

10 less 11 smaller 12 larger 13 dilute 14 more

15 more 16 greater 17 smaller 18 concentrated 19 metabolic waste

1.6 1 kidney failure 2 haemodialysis 3 dialysis machine 4 differentially 5 urea

6 water 7 nutrients 8 Does not contain

Documents

Regulation of water content - Dynbio662.dyndns.info/DSE/WS/ws_E1_ch1_e.pdf1 Nephrons 2 cortex 3 medulla 4 pelvis 5 nephron 6 glomerulus 7 Bowman’s capsule 8 proximal convoluted tubule