Lecture 8 Flashcards
Cells of the body are serviced by 2 fluids
blood
composed of plasma and a variety of cells
interstitial fluid
bathes the cells of the body
Fluids of the Body:
- Cells
- Nutrients and oxygen diffuse from the blood into the interstitial fluid & then into the cells
- Wastes move in the reverse direction
Hematology
is study of blood and blood disorders
Functions of Blood
Transportation
Regulation
Protection
Transportation of?
O2, CO2, metabolic wastes, nutrients, heat & hormones
Regulation:
- helps regulate pH through buffers
- helps regulate body temperature
- -coolant properties of water
- -vasodilatation of surface vessels dump heat
- helps regulate water content of cells by interactions with dissolved ions and proteins
Protection from?
disease & loss of blood
Physical Characteristics of Blood
-Thicker (more viscous) than water and flows more slowly than water
-Temperature of 100.4 degrees F
-pH 7.4 (7.35-7.45)
-8 % of total body weight
-Blood volume:
5 to 6 liters in average male
4 to 5 liters in average female
hormonal negative feedback systems maintain constant blood volume and osmotic pressure
Hematocrit
55% plasma
45% cells
99% RBCs
Blood Plasma
Over 90% water 7% plasma proteins created in liver confined to bloodstream: albumin, globulins, fibronogen 2 % other substances
albumin:
maintain blood osmotic pressure
glubulins (immunoglobulins)
antibodies bind to foreignsubstances called antigens
form antigen-antibody complexes
fibrinogen is used for
clotting
2% other substances =
electrolytes, nutrients, hormones, gases, waste products
Formed Elements of Blood
RBC
WBC
Platelets
WBC (leukocytes)
granular, agranular
granular leukocytes =
neutrophils
eosinophils
basophils
agranular leukocytes =
lymphocytes = T cells, B cells, and natural killer cells
monocytes
Percentage of blood occupied by cells
female normal range 38 - 46% (average of 42%) male normal range 40 - 54% (average of 46%) testosterone
Anemia
not enough RBCs or not enough hemoglobin
Polycythemia
too many RBCs (over 65%)
dehydration, tissue hypoxia, blood doping in athletes
Most blood cells types need to be continually replaced
die within hours, days or weeks
process of blood cells formation is hematopoiesis or hemopoiesis
In the embryo
occurs in yolk sac, liver, spleen, thymus, lymph nodes & red bone marrow
In adult
occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and ends of long bones
Red Blood Cells or Erythrocytes:
-Contain oxygen-carrying protein hemoglobin that gives blood its red color:
1/3 of cell’s weight is hemoglobin
-Biconcave disk 8 microns in diameter:
increased surface area/volume ratio
flexible shape for narrow passages
no nucleus or other organelles
no cell division or mitochondrial ATP formation
Normal RBC count
male 5.4 million/drop —- female 4.8 million/drop
new RBCs enter circulation at 2 million/second
Hemoglobin:
Globin protein consisting of 4 polypeptide chains
One heme pigment attached to each polypeptide chain
each heme contains
an iron ion (Fe+2) that can combine reversibly with one oxygen molecule (Fe = ferric + O = oxygen)
Transport of O2, CO2 and Nitric Oxide:
Each hemoglobin molecule can carry 4 oxygen molecules from lungs to tissue cells
Hemoglobin transports 23% of total CO2 waste from tissue cells to lungs for release
Hemoglobin transports nitric oxide & super nitric oxide helping to regulate blood pressure
iron ions pick up nitric oxide (NO) & super nitric oxide (SNO)& transport it to & from the lungs
Fate of Components of Heme: Iron =
- transported in blood attached to transferrin protein
- stored in liver, muscle or spleen
- -attached to ferritin or hemosiderin protein - in bone marrow being used for hemoglobin synthesis
Fate of Components of Heme: Biliverdin (green) converted to bilirubin (yellow)
bilirubin secreted by liver into bile:
- converted to urobilinogen then stercobilin (brown pigment in feces) by bacteria of large intestine
- if reabsorbed from intestines into blood is converted to a yellow pigment, urobilin and excreted in urine
Tissue hypoxia (cells not getting enough O2)
high altitude since air has less O2
anemia
RBC production falls below RBC destruction
circulatory problems
Kidney response to hypoxia
release erythropoietin
speeds up development of proerythroblasts into reticulocytes
Platelet (Thrombocyte) Anatomy:
Disc-shaped, 2 - 4 micron cell fragment with no nucleus
Normal platelet count is 150,000-400,000/drop of blood
Other blood cell counts
5 million red & 5-10,000 white blood cells
Platelets–Life History:
Short life span (5 to 9 days in bloodstream)
formed in bone marrow
few days in circulating blood
aged ones removed by fixed macrophages in liver and spleen
Complete Blood Count:
Total RBC, WBC & platelet counts; differential WBC; hematocrit and hemoglobin measurements
Normal hemoglobin range
infants have 14 to 20 g/100mL of blood
adult females have 12 to 16 g/100mL of blood
adult males have 13.5 to 18g/100mL of blood
