excreation Flashcards
1
Q
define excretion
A
the removal of metabolic waste from an organism
2
Q
define secretion
A
the release of useful substances like saliva and enzymes from cells or glands
3
Q
define egestion
A
he removal of undigested food solid waste from the digestive tract in the form of faeces = defaecation
4
Q
define metabolism
A
chemical reaction that take place within every cell of the body. These can be building up (anabolic) or breaking down (catabolic)reactions
5
Q
renal meaning
A
relates to the heart
6
Q
deamination
A
removal of an amino group from amino acids
7
Q
what are the different excretory organs and their products
A
- Lungs - carbon dioxide and water from cellular respiration are exhaled into the air
- Skin - mineral salts,traces of urea and water are extracted from the blood and release as perspiration ( sweat)
- Liver - urea from deamination of excess amino acids and bile pigments from breakdown of haemoglobin are released as faeces
- Colon - bile pigments , excess mineral salts from the breakdown of haemoglobin in the liver is released s faeces
- Kidney - urea, mineral salts from excess taken in with food and water from excess water consumed and taken in as food is released an urine
8
Q
define osmoregulation
A
is the control of water levels in the body
9
Q
define adipose
A
fat tissue
10
Q
what is the renal artery
A
the artery that brings oxygenated , unfiltered blood to the kidney
11
Q
what is the renal vein
A
the vein that carries deoxygenated, filtered blood from the kidney
12
Q
what is the renal capsule
A
it is the outer membrane covering the kidney
13
Q
the function of the urinary system
A
the kidneys performs the following four main functions of the urinary system
- Osmoregulation - regulation of levels of H20 in the body fluids
- Excretion - removal of nitrogenous waste e.g urea
- Regulation of pH of bodily fluids
- Regulation of salt concentration of body fluids
14
Q
the structure of the urinary system
A
- it consists of two kidneys with the adrenal gland on top of each, 2 ureters, the urinary bladder and the urethra
- the renal artery transports in oxygenated, unfiltered blood into the kidney
- the kidney filters the blood
- the renal vein transports deoxygenated, filtered blood away from the kidney
- the right kidney is lower than the left kidney
- the ureter tube extends from each kidney and opens separately into the bladder
- the bladder is a thin walled muscular sac in which urine is temporarily stored
- a single tube, the urethra , transports the urine from the ladder to the exterior
- a sphincter muscle at the base of the bladder ,controls the flow of urine to the urethra
15
Q
what are the kidneys
A
they are bean shaped structures that are found half-way down the back just under the rib cage that weight between 115-170 grams each depending on the age and gender of the person and are 11 cm long in height
16
Q
the external structure of the kidney
A
- they are dark red bean shaped and located half*way down the back just under the rib cage
- protected by adipose tissue
- covered by a renal capsule which protects the kidney and its internal structures from infections
- the hilum is the area where the blood vessels enters and leaves the kidney. It is also the area where the ureters leaves the kidney
- the renal capsule is he thin outer membrane covering the kidney
17
Q
the internal structure of the kidney
A
- the kidney is divided into two regions : the outer cortex and the inner medulla
- the medulla is made of a number of cone-shaped pyramids that contains a number of tube called a ducts of Bellini
- the ducts of Bellini lead into the calyces
- the ureter extends into the kidney as a wider pelvis. -
- the pelvis branches into a number of calyxes
- the number of calyxes encloses the apex of the pyramid
- there are 1 million nephrons embedded in the kidney
18
Q
what is the nephron
A
it is a structural and functional structure of the kidney.
this means that the nephrons are the building blocks making up the kidney that are independent units that performs the functions of the kidney
19
Q
the nephron is made up of 2 parts
A
the malpighian body and the renal tubules.
the malpighian body is found in the cortex of the kidney while the renal tubules is extended into the medulla of the kidney
20
Q
the malpighian body is made up of 3 parts
A
- the network of capillary blood networks : the glomerulus
* the Bowman’s capsule
21
Q
what is the other name of the glomerulus
A
the 1st capillary network
22
Q
the structure of the malpighian body in details
A
- the capillary blood vessels of the glomerulus is lined with a single endothelial tissue layer with pores between the endothelial cells
- the AFFERENT arteriole transports blood to the glomerulus
- the EFFERENT arteriole transports blood away from the glomerulus
- The glomerulus lies within a cup-shaped capsule called the Bowman’s capsule
- the space between the inner and outer wall of the Bowman’s capsule is called the capsular space
- the inner walls of the Bowman’s capsule consists of specialized cells called the Podocytes
- the podocytes are cells with small projections between which small openings, the filtrates slits occurs
- the cavity between the inner and outer wall of the bowman’s capsule is known as the cavity of the bowman’s capsule
23
Q
the renal tubules is made up of 3 tubules
A
- the proximal convuluted tubule
- the loop of Henle
- the distal convuluted tubule and the collection ducts
24
Q
what is the renal tubule
A
it is a long convuluted tubule that is situated partially in the cortex and partially in the medulla
25
the renal tubules in detaila
* the Proximal convuluted tubule follows directly after after the Bowman's capsule in the cortex
* convuluted means twisted
* the renal tubule is at its widest in this part and is lined with a single layer of cuboidal epithelium crating a large surface area
* the Loop of Henle consists of 3 limbs:(1) descending limb- which extends down into the medulla and forms a (2)hairpin loop (3) the ascending limb- which extends up into the cortex and made up of cuboidal epithelium with a brush border
* the loop of Henle is situated in the medulla
* the Distal convuluted tubule is situated in the cortex and id lined with cuboidal epithelium
* the distal convuluted tubule leads into the Collecting duct that continues into the medulla from the renal cortex
* a few collecting ducts converge and forms the Ducts of Bellini
* the ducts of Bellini are the tubes forming the pyramids that open into the renal calyx of the renal pelvis
26
explain the blood supply of the kidney in lovely details
- the renal artery is a branch from the aorta that carries oxygenated, unfiltered blood into the kidney
- it enters the kidney at its Hilum
- it branches of into smaller arterioles until it forms the Afferent arteriole supplying each nephron
- the afferent arteriole extends into the Bowman's capsule where it branches to form capillaries of the glomerulus
- the blood capillaries then merge and forms the Efferent arteriole which leaves the Bowman's capsule
- The efferent arteriole then branches to form a second capillary network, The Peritubular capillary network, which surrounds the renal tubule
- the Peritubular capillaries combine to form the venules and larger veins that eventually forms the renal vein and leaves the kidney
27
what does the formation of urine involve
1. glomerulus filtration
2. tubular reabsorption
3. tubular secretion
4. excretion
28
composition of the human blood
* liquid plasma - water, dissolved gasses and useful substances glucose and amino acids =55%
* leukocytes ( white blood cells) and platelets =1%
* erythrocytes (red blood cells) =45%
29
explain the process of the glomerulus filtration
1. it occurs in the malpighian body in the cortex of the kidney
2. due to the diameter of the Afferent arteriole being wider than that of the Efferent arteriole, the blood in the glomerulus is under high pressure
3. the thin endothelium with pores lining the blood capillaries of the glomerulus together with podocytes layer filtration slits of the Bowman's capsule form an ultrafine filter , through which the filterable parts of the blood are forced out.
4. only small dissolved substances travel through the filtration slits of the podocytes, Large proteins and blood cells remain in the blood
5. the part of the blood that moves into the Bowman's capsule is known as glomerulus filtrate and contains both useful and waste substances
30
what are the useful substance in the blood that are involved in glomerulus filtration
water, amino acids , glucose, vitamins, mineral salts
31
what are the waste products in the blood involved in glomerulus filtration
urea, uric acids, creatinine
32
what is meant by the glomerulus filtration is a non selective process
it means that both useful substances and waste products are filtered into the Bowman's capsule
33
what is the glomerulus filtration process promoted by
* The high blood pressure in the glomerulus
* a large filtrate surface
* the permeability of the glomerular membrane
34
how is the malpighian body for filtration
* The Afferent arteriole is wider than the Efferent arteriole , which causes a high blood pressure in the glomerulus , promoting filtration
* The capillary network of the glomerulus has a larger surface area, which increases the filtration efficiency of filtration
* The Bowman's capsule is cup-shaped,which provides a large surface for effective filtration
* The endothelial layer of the glomerular capillaries and the podocyte layer of the Bowman's capsule form an ultrafine filtration through which substances are filtered
* the endothelial layer has pores that only allow smaller parts of the blood to filter through
* the podocytes have filtration slits that only allow smaller parts of the blood to filter through
35
what happens during tubular reabsorption
* this takes place in the proximal convuluted tubule
* useful substances which passed through the glomerular membrane during filtration are actively reabsorbed back into the bloodstream
* this process prevents useful substances forming part of urine and being excreted
36
why does 65% of the water move back into the blood of the peritubular capillaries by osmosis
it is to prevent dehydration and unnecessary loss of important substances
37
why is tubular reabsorption efficient
active transportation needs energy :
+ cuboidal epithelial cells lining the tubules have many mitochondria and microvilli to maximise absorption. The movement of water is passive
+ the loop of henle ensures that water is conserved and recovered from filtration to the blood.
+ cells in the ascending loop of henle are are impermeable to water
+ the medulla is hypertonic because salt is being actively pumped out of the loop into the medulla
+ a steep gradient occurs between the tubular filtrate and the medulla tissue
+ the distal convuluted tubules and the collecting duct are permeable to water . water passively flows by osmosis into the medulla and back to the peritubular capillary during filtration
*the level of hydration of the body fluids determines the amount of water that moves out of the filtrate
38
adaptations of the proximal convoluted tubule for reabsorption
* tube is long and convuluted which enlarges the surface for maximal reabsorption
* the peritubular capillary network surrounds the renal tubule so that reabsorbed substances can easily move into the bloodstream
* the cuboidal epithelial cells , which line the tuule , have many mitochondria to provide energy
* the cuboidal epithelial cells have finger -like projection which increases the absorption surface
39
explain what tubular secretion/excretion is all about
tubular secretion involves the active removal of unnecessary substances from the blood in the peritubular capillaries into the tubular filtrate in the distal convuluted tubule. This substances include ammonia, potassium/hydrogen/sodium ion and drugd
40
the formation and excretion of urine
+ the filtrate flows into the collecting ducts and is now called urine
+ several collecting ducts combine and forms the ducts of bellini , which form the renal pyramids that opens into the renal calyces of the renal pelvis
+ urine flows through the ureter into the bladder
+ urine is temporarily stored in the bladder to the exterior by the urethra
+ this process is called urination
+ both voluntary and involuntary muscle play a role in urination
41
homeostatic control of the blood pH
the ability of the distal convuluted tubule to take up hydrogen and bicarbonate ions is important for the regulation of the pH of the blood . maintaining homeostasis
42
what does a high concentration of hydrogen ions do to the ph of the blood
The low pH ( acidic pH) is due to high hydrogen ion concentration
43
what does a high concentration of bicarbonate ion do to the ph of the blood
High pH ( alkaline pH) is due to high bicarbonate ions
44
the ability of the human body to maintain a stable internal environment
homeostasis
45
the 3 homeostasis mechanism the kidney is involved in
* the regulation of the pH of the blood
* the regulation of the water levels/ osmoregulation
* the regulation of the salt levels in the blood
46
what is osmoregulation
it is the homeostasis control of water and salt levels in blood and tissue fluid
47
produced by the hypothalamus and secreted from the pituitary gland
ADH ( anti-diuretic hormone) and it helps to limit the water loss in urine and prevent dehydration
48
why is sodium important in the body
it is important for food nerve and muscle functioning
