Model Answer Mid Term 2009

Cairo University – Department of Zoology

Mid-Term Exam in Physiology - Hematology For 3rd year Students (Chemistry /zoology) April 2009 :‫الرقم‬

Time allowed 40 Minutes : ‫االسم‬ 15

{A} Complete the following with suitable scientific words:

(3 Marks)

1- Insensible water loss takes place by evaporation from the respiratory tract (400 ml/day) and diffusion through the skin (400 ml/day). 2- Cerebrospinal fluid (CSF), eye humors (aqueous & vitreous), synovial fluid, gastrointestinal secretions (digestive juices), mucus, peritoneal fluid, pericardial fluid , tears, …. etc are examples of transcellular fluids. 3- The principle extracellular cation is Na+ while the principle intracellular cation is K+. 4- Blood is used for transportation of dissolved gases such O2 and CO2, metabolic waste products, hormones, enzymes, absorbed nutrients, metabolites, plasma proteins and WBCs & RBCs. 5- The viscosity of whole blood is strongly influenced by three factors which are hematocrit and chemical composition, temperature and the flow rate of blood. 6- Stem cells are characterized by immortal, undifferentiated and pluripotent. {B} The following sentences may be right or may be containing one wrong word. Put (√) in front the right one and a line under the incorrect word then write a correct word above it. (3Marks) 1- The water loss in feces can increase to several liters per day in people with severe diarrhea. (decrease) 2- Blood volume increases in circumstances such as increase in the cell number as in cases of polycythemia and leukemia. 3- The pH of blood must remain in the range of 7.35 to 7.45. 4- Whole blood has a relative viscosity of 4.7 in males and 4.4 in females. 5- Hydrostatic pressure tends to expel fluid from the blood. 6- Tonicity is determined by the response of a cell when it is placed in a solution. {C} Mention one difference only between the following scientific terms: (3.5 Marks) 1Plasma Serum Has fibrinogen and other clotting Has not fibrinogen and other clotting -1-

2-

3-

4-

5-

6-

7-

factors.

factors.

Oxygenated blood Oxygenated blood is bright red as O2 impacts a strong red color to the heme group. LDL (low denslty lipoprotein) It transports cholesterol to the arteries and can be retained there starting the formation of plaques, increased levels are associated with atherosclerosis, and thus heart attack, stroke and peripheral vascular disease. @ For this reason, cholesterol inside LDL lipoproteins is often called "bad cholesterol". Erythrocytes (red blood cells) (RBCs)

Deoxygenated blood Deoxygenated blood is a darker shade of red or less redness and more blueness. HDL (high denslty lipoprotein) It can remove cholesterol from the walls of blood vessels and transport it back to the liver for excretion or reutilization.

@ This is the main reason why HDLbound cholesterol (HDL-C) is sometimes called "good cholesterol". Leukocytes (white blood cells) (WBCs) @ Mammalian erythrocytes loose their @ With nuclei and organelles and nuclei when mature and other some have granules organelles including their mitochondria. @ Small than WBCs. @ Larger than RBCs. @ Red. @ Colorless. @ Have Hb. @ Lack Hb. Plasmolysis. Cytolysis When the cell is placed in a hypertonic When the cell is placed in a solution. hypotonic solution. @ Water diffuses out of the cell till @ Water diffuses into the cell till equilibrium is reached. equilibrium is reached. @ Shrinking or crenation of RBCs @ The cell causes it to swell and takes place and they may be die. often burst. Plasma Interstitial fluids @ Water is about 4% body weight = ~ @ Water is about 15% body weight = about 11 liters. 3 liters. @ Has a higher concentration of @ Has a lower concentration of protein. protein. Leukocytosis. Leukopenia (leucopenia) A raise in WBCs count above the A decrease in white blood cell count normal range (11,000 WBCs/1 mm3). in the circulating blood below the normal range (4,000 – 5,000 WBCs/ 1 mm3)

{D} Write briefly on the following: (3 Mark) 1- Mention TWO only of the main characteristics of markers (indicators) that used for measurement of body fluid compartments. 1- They disperse evenly in the compartment. -2-

2- They remain in the compartment being measured. 3- Dispersion takes place only in the compartment. 4- They are not metabolized or excreted. 5- They are not toxic. 6- They are easily measurable (chemically, photoelectrically or by other means). 7- They do not alter water distribution. 2- Regulation of fluid intake (gain)

3- Explain how erythrocytes play an important role in the body's immune response. When RBCs are lysed by pathogens such as bacteria, their hemoglobin releases free radicals. These free radicals break down the pathogen's cell wall and membrane, leading to kill pathogens. {E} Define the following scientific terms: (1 Marks) 1- Homeostasis: The ability to maintain a relative constancy of the internal environment is known as homeostasis. 2- Erythropoiesis. It is the regulation and production of RBCs. {F} Write the scientific name of each of the following: (1.5 Marks) 1- It is the liquid within the cell membrane. It represents 2/3 of total body water (~ 40% body weight) (~ 30L). It is responsible for metabolic reactions. (

Inracellular fluid

2- It is main contributor to colloid osmotic pressure of the blood.

)

( Albumin ) -3-

3- It is the ratio of the weight of blood to the weight of an equal volume of water at 4 ºC.

(

The specific gravity of the blood

)

4- It is is the unit of dynamic viscosity which equal to one dyne-second per square centimeter (dynes-s/cm2) (N-s/m2). ( Poise {P, Ps, or Po}

‫أجمل األمنيات بالتوفيك والتفوق‬ ‫ شـــبل شــــعالن‬.‫د‬.‫أ‬

-4-

)