Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

human physiology > excretory system > Flashcards

excretory system Flashcards

1
Q

toxic metabolic wastes

A

nitrogenous wastes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

most toxic nitrogenous waste

A

ammonia, excreated out in forms of urea and uric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

process of removal of nitrogenous wastes

A

excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

osmoconformers

A

Osmoconformers are animals that do not actively control The osmotic concentration of the body fluids. They change body Fluids according to the osmolarity of the surrounding medium.

Marine and freshwater invertebrates and vertebrate hagfish(myxine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

osmoregulators

A

maintain an internal osmolarity, different from the surrounding medium that they inhabit by taking in or releasing fluids from their bodies with the expenditure of energy.

most aquatic vertebrates are strict osmoregulators except sharks and rays and hagfish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the osmolarity of fresh water and of freshwater organisms

A

50 mOsm per litre and 200-300 mOsm per litre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how do freshwater organisms combat loss of salts and entry of water from the environment

A

protozoa like amoeba and paramoecium have special contractile vacuoles that pump out excess water

other organisms have
scales of adipose
do not drink water
dilute urine
presence of ionocytes like chloride that can readily uptake salts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

osmolarity of seawater

A

1000mOsm per litre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how do marine and bony fishes prevent water loss in a hypertonic environment

A

the fish
drink seawater
the cl cells of gill membranes help eliminate excess monovalent ions from body fluid to seawater and divalent cations are eliminated through faecal matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

name two osmolyte

A

urea and trimethylamine oxide.. they raise osmolarity of the body like in hagfish to make them isotonic to the environment, or slightly hyperosmotic like in sharks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

percentage of water required to keep a human alive

A

at least 88% if they lose 12% of water, they die.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how do desert animals compensate for water loss

A

they can recover 90% water from metabolic water. once water is available,they rehydrate. example, a can drink 80L of water in 10 mins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

different classifications of animals based on their excretory products

A

ammonotelism: ammonia, requires large amounts of water to be excreted
found in many bony fishes, aquatic amphibians and aquatic insects such as amoeba,sponge,hydra,cray fish,bony fish and frog tadpole
excreted through diffusion from body surfaces or gills as ammonium ions

ureotelism:terrestrial adaptation, less toxic nitrogenous waste, as urea and uric acid for the conservation of water.urea can be tolerated more as it is 100000 times less toxic than ammonia
in mammals,land amphibians like adult frog and some marine fish

uricotelism:reptiles,birds,land snails,insects. uric acid excreted in form of pellets or gel paste. insolube in water.its important for organisms producing shelled eggs, as uric acid being insoluble precipitates with the egg shell only and doesn’t enter the embryo and harm it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

the ornithine cycle step by step

A

aka kreb henseleit cycle, occurs in the liver

  1. co2+ATP+NH3-> carbonyl phosphate
  2. carbonyl phosphate+orthinine-> citrulline
  3. citruline+aspartic acid->arginosuccinic acid
  4. arginosuccinic acid->fumaric acid+arginine
  5. Arginine+water->urea +orthinine
  6. the orthinine generated is used in step 2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

different excretory structures in different animals

A

vertebrates: tubular organs called kidneys

Platyhelminthes(like flatworms), rotifers, some annelids and cephalochordate amphioxus: protonephridia/flame cells mainly concerned with osmoregulation

annelids like earthworms: tubular nephridia which remove nitrogenous wastes and help keep an ionic and fluid balance.

insects like a cockroach: Malpighian tubules. help in the removal of wastes and osmoregulation

crustaceans like prawns: green glands/antennal glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

types of nitrogenous wastes

A
  1. ammonia: most toxic protein metabolic waste requires a lot of water for its removal. produced in the lives by deamination
  2. urea: white crystal solid produced by the liver, less toxic, made with CO2+ NH3
  3. uric acid: produced in the liver, semisolid saves water. found in phosphate-rich bird droppings
  4. :xanthines and guanines: nucleotide metabolism found in spiders and penguins
  5. Trimethylamine oxide: specialised product in marine bony fishes
  6. ornithuric acid: in birds
  7. Hippuric acid: produced from benzoic acid in mammals
  8. creatinine: from creatine phosphate present in muscles. increased levels indicate kidney damage.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

urea level in blood

A

18-38mg/100 ml of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

kidneys location

A

reddish-brown, bean-shaped at the last thoracic and 3 lumbar vertebrae,close to the inner wall of the abdominal cavity.
left kidney is a little higher than the right one due to the space being occupied by the liver on the right side. it is the opposite in other mammals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

weight of a kidney

A

120-170 gms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

place on the kidney from where vessels, ureters and nerves emerge

A

hilum, at the inner concave notch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

3 protective coverings of the kidney

A
  1. renal fascia: outermost fibrous covering linking it with the abdominal wall. the kidneys are fused with the body wall on the dorsal side. the peritoneal cover is present on the ventral side, making it retroperitoneal arrangement
  2. adipose capsule: middle covering involving adipose tissue and acts as a shock absorber
  3. renal capsule: it is the innermost tough protective cover made up of white connective tissues, with a few elastic fibres and few muscles.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

internal structure of the kidney

A

inner to the hilum is the broad funnel-shaped base called renal pelvis lined by transitional epithelium with projections called calyces
the outer layer is a tough capsule
there are two zones, the outer cortex and inner darker medulla. the medulla is divided into few conical masses called the medullary pyramids which project into the calyces.
the cortex that extends to the calyces and is in between the pyramids is called columns of Bertini

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

the renal pyramids

A

larger base towards the cortical side and apex called renal papilla towards the cavity. the papillae project into the cavity forming minor calyces which join to form major calyces.
medulla region has a higher osmotic concentration equal to 1200mOsm/L due to conc of NaCl and urea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

cortex close to the medulla region

A

juxtamedullary area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

ureters

A

pair of whitish distensible muscular tubes of 25-30 cm in length and 3mm in diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

walls of ureter

A

adventitia, middle muscular and inner mucosa. the muscles are always undergoing peristalsis.
outer longitudinal, middle circular and inner longitudinal muscles of the muscular coat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

urinary bladder

A

median pyriform sac
the fully distended bladder becomes ovoid in shape
has three parts, apex fundus and neck
fundus has a triangular area called trigone. it has openings of ureters and internal urethral orifice
neck region has two sphincters, involuntary internal sphincter and external voluntary sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

walls of the urinary bladder

A

outer adventitia made of soft connective tissue
middle muscular layer aka the detrusor muscle.has involuntary circular muscles in the middle and longitudinal on the sides.
inner mucosa has loose connective tissue towards the side and transitional epithelium/ureothelium towards the luemn.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

urethra

A

only in mammals
straight in females,2-4 cm long, the urinary aperture in the vulva in front of the vaginal aperture.
in males, it is 20cm long, passes through prostate ad the cowpers glands and also releases sperms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

structural and functional unit of the kidney

A

nephron/uniferous tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

parts of the nephron

A

glomerulus and renal tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

glomerulus

A

tuft of capillaries by branching of afferent arterioles of the renal artery . the glomerular capillaries join to form the efferent arteriole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

components of renal tubule

A

bowman’s capsule
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

describe the bowman’s capsule

A 
blind double walled cup shaped structure which encloses the glomerulus
two layers-
visceral layer(inner wall):flat squamous epithelial cells on the periphery and specialised podocytes in the middle part.they enclose slits called filtration pores

parietal layer(outer wall):flat squamous epithelium

spaceb/w the two layers is known as capsular space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what does the malphigian body consist of

A

glomerulus along with bowmans capsule

aka renal corpuscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

proximal convulated tubule

A

lower part of bowmans capsule leads to pct
highly coiled surrounded by peritubalar capillaries
lined by cuboidal long brush border epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

function of pct

A

there cells have abundant mitochondria, to perform active absorption and secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

loop of henle

A

hairpin like tube which descends into the medulla it has a descending limb(L) and ascending limb(R)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is the distal convoluted tube

A

the ascending limb continues as the dct, a highly convoluted tube lying close the malpighian body

40
Q

what are the collecting ducts

A

the dct of many nephrons open into a straight tube called collecting duct,many of which open into renal pelvis through medullary pyramids in the calyces. though they start from the cortex

they enter the medulla and form ducts of bellini

41
Q

what is the vasa recta

A

U shaped minute vessel of the peritubular capillaries that run parallel to the loop of henle

42
Q

where is vasa recta highly reduced or absent

A

cortical nephrons

43
Q

two types of nephrons

A

cortical nephrons:most abundant. the loop of henle is too short and barely extends into the medulla
juxtamedullary nephrons:very few, the loop of henle is long and extends into the medulla

44
Q

which parts of the nephron are part of the medulla

A

loop of henle and collecting tubules

45
Q

what is the juxtaglomerular apparatus(JGA)

A

the epithelial cells of the distal convoluted tubule come in contact with the afferent and the efferent arterioles and are more dense than the other tubular cells and collectively called macula densa. along the side of macula densa,the wall of afferent arteriole contains modified smooth muscle cells called juxtaglomerular cells. with the macula densa,they make up the JGA.

release renin which regulates blood pressure and glomerular filtrate rate.

46
Q

steps in urine formation

A

glomerular filtration
reabsorption
secretion

47
Q

how much blood is present in the kidneys at a given time

A

1.1-1.2 L , 20%of total blood volume

48
Q

where is glomerular filtration taking place

A

glomerulus

49
Q

how does glomerular filtration take place

A

the glomerular capillary blood pressure causes the filtration through three layers
the endothelium of glomerular capillaries which have small holes called fenestra
the epithelium of Bowman’s capsule made of podocytes arranged in such a manner that there are slit pores formed
the basement membrane between these two layers

50
Q

what is ultrafiltration

A

glomerular filtration

51
Q

what does glomerular filtrate contain

A

everything except proteins passes into the lumen of Bowmans capsule. the proteins leave via the peritubular tubules then via the vasa recta.

52
Q

development of filtration pressure

A

the large diameter of afferent arteriole compared to efferent arteriole

53
Q

blood pressure in glomerular blood(GHP)

A

60mm Hg aka glomerular hydrostatic pressure

54
Q

blood colloidal osmotic pressure(BCOP)

A

osmotic conc. of proteinaceous content of glomerular blood

30mmHg

55
Q

capsular hydrostatic pressure(CHP)

A

the pressure of interstitial fluid and pressure of renal filtrate
20mmHg

56
Q

glomerular filtration pressure

A

the pressure exerted on the blood undergoing filtration
GHP-(BCOP+CHP)
60-50
=10mmHg

57
Q

glomerular filtration rate

A

180 litres per day

58
Q

autoregulation of glomerular filtration

A
  1. myogenic autoregulation(decreases): rise in blood pressure, increasing the passage of calcium ions due to stretching of vascular walls of the glomerulus. the calcium ions cause the cells to contract and hence check the overstretching of the vascular walls and raise vascular resistance so that the gfr is brought back to normal
  2. juxtaglomerular apparatus(Increases): at he location of contact between dct and afferent tubules. they release renin when a decrease in blood pressure and GFR. the renin converts angiotensinogen to active hormone angiotensin by constricting the efferent arteriole, therefore, restoring GFR
  3. neural control(decrease): sympathetic nervous system, constriction of renal arteries, causes the decrease in renal blood flow and GFR
59
Q

where does tubular reabsorption take place

A

mainly in proximal convoluted tubule

60
Q

what is tubular reabsorption

A

reabsorbing essential items from the primary glomerular filtrate (99% from 180 L per day of filtrate formed)

61
Q

what is absorbed passively in tubular reabsorption

A

nitrogenous wastes

water in the initial parts of the nephron

62
Q

what is absorbed actively in tubular reabsorption

A

glucose, amino acids, sodium

63
Q

what is tubular secretion?

A

secretion of metabolic wastes from tubular cells into the filtrate. it includes secretion of K+,h+,ammonia,hippuric acid,creatinine.drugs,pigments,toxins.
helps in the ionic and acidic balance of body
its the only mode of excretion in animals with no glomeruli like desert animals and amphibians.

64
Q

function of pct

A

absorption of 70-80% of electrolytes and water due to cuboidal brush border epithelium
helps maintain pH, ionic balance
absorption of HCO3-
secretion of ammonia and hydrogen and potassium

65
Q

the function of loop of Henle

A

The primary function of the Loop of Henle is the recovery of water and sodium chloride from the filtrate. Hence the function of Loop of Henle is the conservation of water.

  1. the thin descending limb, it is permeable to water but impermeable to electrolytes, it releases water back into the body(medullary fluid)
  2. the thick ascending limb, from the concentrated urine,ions and electrolytes(nacl) are released back into the blood
66
Q

function of dct

A

reabsorption of na and water and HCO3
selective secretion of K, H, NH3
maintains pH, K Na ion balance

67
Q

the function of collecting tubules

A

they reabsorb the water and also some urea which makes its way to the medullary region of the loop of Henle, hence facilitating more absorption of water back into the body via osmosis from the descending limb(aka urea recycling)

pH, secretion of hydrogen and potassium, ionic balance

68
Q

mechanism of concentration of the filtrate

A

based on the length of the loop of Henle
the flow of filtrate in the two limbs of Henle in opposite directions and thus forms a counter current(even in the vasa recta)
the counter-current helps maintain an increasing osmolarity towards the inner medullary interstitium
300mOsmL in cortex to 1200 in the medulla. this gradient is mainly caused by NaCl and urea.

NaCl transported by ascending limb of the loop of Henle- exchanged with descending branch of vasa recta-nacl returned to interstitium by ascending portion of vasa recta( counter-current mechanism)

this helps in drawing out water back into the body and concentrating the filtrate by at least 4 times than initial filtrate.

69
Q

regulation of kidney function by ADH

A

excessive loss of fluid activates receptors in the hypothalamus to release vasopressin from the posterior pituitary and absorb water from latter parts of the nephron
it can also increase blood pressure and GFR

70
Q

deficiency of ADH

A

diabetes insipidus

71
Q

regulation of kidney function by JGA

A

operates a multi hormonal renin-angiotensin-aldosterone system (RAAS)
when there is a drop in the GFR, the renin released converts the angiotensinogen from the liver to active peptide hormone angiotensin 1 which converts(angiotensin-converting enzyme from lungs ) further to angiotensin 2. angiotensin 2 constricts the efferent arterioles to constrict and more blood in the glomerulus.
signals more reabsorption of NaCl and water from the pct
stimulates the adrenal gland to absorb more water and ions from distal parts of the tubules.
so increases blood pressure and volume, and GFR.

72
Q

atrial natriuretic factor(ANF)

A

opposes RAAS
released by the wall of the atria when there is an increase in blood volume and pressure.
vasodilation of blood vessels
inhibits the reabsorption of na+ by the distal tubules(collecting duct) and reduces the release of aldosterone from the adrenal gland. it also increases the excretion of Na+ from the urine.

73
Q

what causes micturition

A

the voluntary signal is given by the CNS, contraction of the walls of smooth muscles in the urinary bladder and relaxation of the sphincter.
this mechanism is called micturition reflex

74
Q

indication of diabetes mellitus

A

glucosuria and ketonuria in urine

hyposecretion of insulin

75
Q

albumin in urine disorder

A

injury in the renal tract, glomerulonephritis

76
Q

bile salts and pigments in urine

A

jaundice, bile is excreted via poop

77
Q

glucosuria

A

glucose in urine

78
Q

ketonuria(acetoacetic acid, hydroxybutyric acid)

A

diabetes mellitus or prolonged fasting

79
Q

creatinine in urine

A

hyperthyroidism, starvation

80
Q

uremia

A

accumulation of urea in the blood,can cause kidney failure

81
Q

nephritis

A

inflammation of the kidney

82
Q

glomerular nephritis

A

inflammation of the glomerulas

83
Q

pyelonephritis

A

inflammation of the kidney in the pelvis region

84
Q

cystitis

A

urinary bladder inflammation

85
Q

renal calculi

A

stone or oxalate masses in kidney

86
Q

polyurea

A

excessive urine passed out

87
Q

alkaptonuria

A

a genetic disease where homogentisic acid is excreted out with urine

88
Q

pyuria

A

pus in the urine

89
Q

haematuria

A

blood in the urine

90
Q

average urine expelled out of the body per day

A

1.5 L

91
Q

urochrome

A

Urobilin or urochrome is the chemical primarily responsible for the yellow colour of urine by
processing of dead blood cells in the liver.

92
Q

haemodialysis

A

artificial kidney
blood taken out of radial artery of the patient cooled to 0 Celcius and mixed with heparin
pumped into a machine
has a cellophane paper impermeable to plasma proteins
the nitrogenous waste diffuse from the blood channels to the outside dialysis fluid
clean blood pumped back into the radial vein

93
Q

kidney transplant

A

treatment of choice for kidney failure, compared with a lifetime on dialysis.

94
Q

what is inulin

A

fructose storage polysaccharide which the body cant metabolised
filtered through kidney
therefore used to check the functioning of kidneys

95
Q

tubular maxima

A

the maximum amount of substance that can be retained by blood after which its excreted out in the urine
glucose:180mg/100ml of blood

human physiology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions