My Homeostasis

7/31/2019 My Homeostasis

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-homeostasis is the maintenance of a costant internalenvironment.

-Affected by 2 factors :-

i.ii.

-urine consist of mainly water and dissolved wasteproducts

Function of kidneys- excretionremove toxic waste products from the blood,eg: urea ,ammonium compounds

-osmoregulationkeeping the osmotic concentration of

the blood constant by getting rid of excess salt and water- maintaining blood pHregulating the excretion of H+

and other ions to adjust pH

- regulating blood volumecontrol the amount of waterloss in urine


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MY KIDNEY

located at the dorsal wall of the lumbar region

of the abdomen

about 10cm,bean-shaped,dark red

Main parts:-

Cortex

Medulla

Pelvis

Blood vessels connected :-- the kidney receives blood from _____ via ___________ .

- within each k_____ , the renal artery divides into smaller and smallerbranches and finally into afferent arterioles.

- each a_____ a________ divides and forms a knot of capillary network

called g__________ within the Bowmans capsule.- blood leaves the glomerulus via the e_______ a________ and flows into asecond capillary network surrounfing the loop of Henle and the proximalconvoluted tubule before flowing into a branch of renal vein.

- branches of renal veins join the renal vein which returns the filtered blood

from the kidney to the vena cava,


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THE NEPHRON

the functional unit of the kidney is the nephron.

the human kidney consists of about 1 million nephrons.

a nephron consists of three major parts:a) glomerulus

b) Bowmans capsule

- double-walled,cup-shaped, structure in the cortex

a) renal tubule

renal tubule is made up of the:

a) proximal convoluted tubule - cortex

b) loop of Henle - medulla

c) distal convoluted tubule cortex connects thecollecting duct that drains into the pelvis.


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ULTRAFILTRATION

1. Bowmans capsule :-

- made up of two layers of cellssurrounding the glomerulus

- spaces between the two layers is thecapsular space

- cells that make up the inner wall ofBowmans capsule are podocytes

- podocytes adhere closely to theendothelial cells of the glomerulus

- podocytes and endothelium ogglomerulus form a filtration membrane

- fm permits the passage of water andsolutes from blood into the capsularspaces

2. Process :-- kidney receives blood from the firstbranch of aorta

- blood is under high pressure when itreaches the nephron

- pressure is maintained and enhanced

- because afferent arteriole has larger

high pressure forces the fluid throughthe filtration membrane and into thecapsular space

- fluid that enter capsular space isglomerular filtrate

- glomerular filtrate has the samecomposition as blood plasma but doesnot contain rbc and plasma protein

- contains water,glucose,urea,salts andother small molecules

- rbc and plasma protein are too largeto pass through filtration membrane

- rbc and plasma protein remain inblood that flows through efferentarteriole

- from the Bowmans capsule, the

filtrate goes down the proximalconvoluted tubule.


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- Loop of Henle long, hairpin-shaped region of nephron descends into themedulla and then returns to the cortex

- Water, sodium and chloride ion are reabsorbed

- The watery filtrate which now is low in salt but retains waste such as urea,

arrives at the distal convoluted tubule.- More water,_____ and ________ ions are reabsorbed

- When the fltrate reaches the collecting duct,very little salt is keft and 99% ofwater has been reabsorbed into the bloodstream. Only 1% water in thefiltrate leaves the body as urine.

- As the urine moves down to the collecting duct ,some urea diffuses into thesurrounding fluid and blood because of its small molecular size

- About 45% of original urea remains in the colllecting duct to be excreted inthe uriine

- After leaving the collecting duct, urone flows down ereters,bladder and

urethra and finally excreted.


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SECRETION

- Process by which waste and excess substances that were notiniltially filtered are secreted into the renal tubule

- Takes place all along the renal tubules and collecting ducts- Active at distal concoluted tubule

- Occurs via passive diff. and active transport

- Secreted subst. :- hydrogen ion,______,_______,_____,

_______, ________, ________,___________

ADVANTAGES

- Helps eliminate and increase rate of waste removal from body

- Helps regulate blood levels of certain ions

- Eg :- 1.


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PORTION OF THE

NEPHRON


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OSMOREGULATION

- Is the regulation of osmotic pressure in the internal environment

- Important to ensure that the tissue fluid and the cell sap are isotonis

to each other ,avoid crenation or haemolysis- Variables affecting osmoregulation:-

- Osmotic pressure in blood plasma depends on the ratio of waterto the dissolved salts,(sodium chloride)

- To control osmotic pressure , the ratio of the volume of water to

sodium chloride needs to be controlled.

- Two importaant hormones are:-

- ADH

- ALDOSTERONE

- ADH is produced by hypothalamus and stored in the posterior lobeof the pituitary gland.


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KIDNEY FAILURE

- Is ___________________________________________________

____________________________________________________________

______________________________________________ .

- If the glomeruli are damaged, _____________________________ .

- Factors :-

- _________________

- _________________

-__________________

- If one kidney fails to function,___________________________________________.

- If both kidney fails :-

- _____________________

-


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HAEMODIALYSIS

- A process of filtering blood using artificial means that replace a fsiled kidney.

- A treatment for ppeople in the later stage of chronic kidney disease or kidneyfailure.

- Concept diffusion through a semi-permeable membrane- Principle ideas :-

- blood is withdrawn from the body from an opening in an artery

- blood is then pumped through the tubing of a dialysis machine tofilter away wate products and to restore its normal constituents

before being returned to the body via the vein.

- How blood is filtered and restored

- the tubing of a dialysis machine is made of partially permeablemembrane (cellophane)

- the tubing is bathed in a dialysis fluid of special composition, called thedialysate.

- when blood flows through the tubing, the fine pores in the wall of thistubing only allow small molecules such as urea and other wasteproducts to diffuse into the dialysate

- macromolecules such as ______ and _________________ cannnotgo through the pores so they remain in the blood inside tubing.


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- other substances such as s________ and g__________ which

are needed in the body are also s______ enough to pass the

pores.

- but these needed substances are prevented from diffusing outof the tubing as the d__________ is made up to have the

same concentration as the normal tissue fluid.

- both dialysate and blood in the tubing has the same

concentration, the outward or inward diff is equilibrium- excess salts,urea and other wastes are absent in the dialysate,

they diff from blood to the dialysate.


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REGULATION OF BLOOD SUGAR LEVEL AND BODYTEMPERATURE


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Notes about Kidney Dialysis:

The main stages that blood passes through during

the dialysis process include:

Blood enters machine from body (underpressure from radial artery).

Pump (some diagrams show a roller pump)

controls pressure and flow rate. Anticoagulant added to prevent clotting. Blood passes through dialysis membrane

(equivalent to kidney nephrons).

Bubble Trap removes any gas bubbles fromblood. Blood is filtered then returned to the patient's

radial vein.

REGULATION OF BLOOD TEMPERATURE


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REGULATION OF BLOOD TEMPERATURE


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SKELETAL MUSCLE ADRENAL MEDULLA GLAND

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My Homeostasis

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