patho sheet # 1 of Dr.Faisal - Yusur Altikriti

Pathology

Lec.1, week 11.
Date: 21\11\2010.


Circulatory disturbances
- 60% of our body weight is fluid, 40% of this fluid is within cells and 60% of it is in between cells (interstitial tissues) or in the intercellular paces and body cavities (pleural cavity, joint spaces ... ect) .
-only 4.5% from fluid that is found in between cells is circulating within the cardio vascular system.


-back to histology:
*Blood vessels composed of 3 layers:
1. Intima.
2. Media.
3. Advantitia.

*between Intima and media there is internal elastic lamina, and between media and adventitia there is external elastic lamina.

*media usually contains smooth muscles EXCEPT for capillaries (the have very thin wall "semi permeable membrane" that can exchange materials like water, some solutes and rarely they can pass proteins).
-theoretically histologists say they may pass proteins BUT practically they can't with exceptions (during inflammation).

*the ability to pass proteins depends on the pores between the endothelial cells, whenever pores increase in their dimensions leakage of proteins takes place.


-there are some forces that govern the exchange of water especially to the outside of the vessels but also to the inside, for example:
1. Intravascular hydrostatic pressure tries to push water outside to the interstitium because of increased volume of water in the capillaries which will lead to increase pressure on walls.
2. Colloidal osmotic pressure (oncotic pressure) because of plasma proteins and it is opposite to the hydrostatic pressure .this will cause water to move from interstitium to the vessels.

***these two cases are NORMAL.

-The abnormal exchange of water is edema (oedema).
*definition: abnormal increase in the interstitial fluid as a result of exceeding pushing of water to the outside of the cardio vascular system over the pulling to the inside.
*classification: 1.localized
2. Generalized
*another classification: 1.Inflammatory: exudate (proteins and other materials) because of increase in permeability of capillary membranes.
2. Non inflammatory: transudate.
-hydrostatic pressure:
*hydrostatic pressure within the interstitium ACTUALLY should push water into the capillaries but IN FACT it tries to drag water outside because it is a negative pressure and this pressure is minor.
*increased hydrostatic pressure maybe due to:
A. increase pressure.
B. removal of the lower limbs.
C. obstruction to the venous drainage.
*example: varicose veins are due thrombosis that will affect the drainage and cause edema because of increase hydrostatic pressure within veins.
*thrombus in deep veins(femoral vein) causes edema due to impediment of the drainage and increased hydrostatic pressure and the result is filtration more than reabsorption.this could be localized or generalize. example of generalized one is the congestive heart failure or left side ventricular failure that will effect cells in the left atrium (not all the blood in the atrium will go to the ventricle and part of it will go to the circulation) and effect the lung causes congestion (the amount of blood is more than needed causes increase hydrostatic pressure and edema.

-lymphatic drainage:
*any obstruction in the lymphatics lead to edema.
*the hydrostatic pressure is dropping and the colloidal pressure is the same or a little more as we go from arteries to veins so we will have a loss in water in the arterial side (filtration) and gain water at the venous side (reabsorption).
*in normal situations the amount of water going out side is more than going to inside so that some of that amount will accumulate in the interstitium at the end of the venules and then will be collected by the lymphatics (lymphatic drainage).

-examples of lymphatic obstruction:
1. Elephantiasis:
-Because of philaria (micro philaria).
-at the end of its life cycle it settles in about the inguinal region of both males and females like the lymphatics of the lower limbs,scritum,external genitalia and inguinal lymphs.
-First it causes chronic lymphadenitis then fibrosis which leads to obstruction and finally impairment of drainage of that target organ.

2. Breast cancer:
A. radial mastectomy with block dissection of axillary content. (Removal of the whole breast).
B.lumpictomy: removal of any lumps.
C.segmentectomy: removal of segments of the breast with or without nipples.

***radiotherapy sometimes may lead to fibrosis.
***in case of impediment drainage from the breast cells in the presence of some parts of the breast there will be dempling in the locations of hair (although there is a little hair) and this will give an external appearance to the skin of the breast called orange peal.

3. Malignant processes:
-permeation by malignant cells in the axilla might impede drainage. So blocking by malignant process will reflex cells on the drainage of upper limbs.
-removal of axillary lymph nodes (indirect obstruction) by surgery leads to lymph edema.
-during inflammation (due to infection, mechanical factors, chemical factors and physical factors) the capillary permeability increases as a result of decrease colloidal pressure and then edema takes place.

-decrease plasma proteins:
1. Decrease supplement of proteins (hypo proteinemia)
-mal nutrition, mal nourishment.
-loss of protein energy.
- 2 types: A.kawshiorkor.
B.marasmus.
-both causes lose of weight.
-in children lose of 80% of the expected weight means mal nourishment.
***kwashiorkor is more severe than marasmus although weight loss is less than in marasmus (because it contains more water).

2. Impaire protein synthesis
-in chronic liver disease (serosis due to alcohol or viral infection) the effect will be on the proteins in all over the body and may cause edema.

3. Protein losing diseases
A. celiac disease (gluten sensitive interopathy):
-hyper sensitivity to certain cereals (contains gluten "gliaden protein" which is an interopathy that causes hyper sensitivity).
-if we made a cross section in the small intestine we will find that it has villi covered by microvilli which is covered by interocyte made for absorption .in this disease the tips of the microvilli broaden and shorten till they reach atrophy "extremes of this cause total villus atrophy" causes reduction in the surface area and decrease in absorption so whatever he/she eats will exit at the SAME.
B.nephrotic syndrome:-glumerulus nephrons don't leak proteins.
-in some diseases proteins will leak to the urine (protein urea)because of distortion in the pores.

Corrections are welcomed,
Done by: Yusur Al-Tikriti.