Chapter 17- Blood Flashcards
Blood Functions
- Transport
- Maintenance
- Protection
Transport Blood Function
Oxygen and nutrient delivery to tissues
Waste removal from tissues
(nitrogenous and carbon dioxide)
Hormone transport to target organs
Maintenance blood function
Body temperature (blood is mostly water and water absorbs heat and maintains 98.6)
pH (all chem reactions take place with a limited set of pH volumes)
Fluid volume (blood pressure and circulation)
Characteristics of Blood
Scarlet to dark red in color
pH Range- 7.35-7.45
Viscous (thickness) due to erythrocytes (red blood cells)
What causes the color difference in blood?
Oxygen content of the blood
Red blood cells have hemoglobin that binds and carries oxygen (causes redness)
Blood Composition
Blood Plasma
Blood Cells
Blood Plasma
The fluid portion of blood (non-living)
90% water
6 solutes found in plasma
(Electrolytes, nitrogenous substances, organic nutrients, respiratory gasses, hormones, plasma proteins)
Electrolytes
Found in plasma
Most numerous
Nitrogenous substances
Found in plasma
Urea, uric acid
Organic nutrients
Found in plasma
Glucose, amino acids, triglycerides, tc.
Respiratory gasses
CO2 found more here than in erythrocytes
Hormones
Found in plasma
Plasma Proteins
Make up most of the mass of the plasma
Mostly produced by liver
Serve as carrier/transport protein that bind to another substance and allow it to move through the blood to used by cells for energy or nutrients
Albumin
Type of plasma protein
Prevents water from leaving the bloodstream
Major transport protein of blood and contributes to osmotic pressure (water moving into a more concentrated substance) in capillaries
Found in blood vessel stream and because it is so large in size, water will be pulled towards it
What would happen to water in the blood plasma if albumin were absent?
If absent, water would leave the bloodstream
BP would tank
If water enters all body tissues, you would flood the tissue with water and can impair their function
What would happen to water in the blood plasma if albumin were absent?
If absent, water would leave the bloodstream
BP would tank
If water enters all body tissues, you would flood the tissue with water, and can impair their function
Blood Cells
Short-lived (at MOST, 4 months, some 5-10 days)
Non-mitotic (will not divide)
Built-in mechanism to produce more of these blood cells for the lifetime
Erythrocytes
Red blood cells
Respiratory gas transport
Hematocrit
Hematocrit
Portion of total blood volume made up by erythrocytes
Males- around 47%
Females- around 42%
showing a small influence of testosterone on red blood cell hematocrit
Leukocytes
White blood cells
Protection/infection
Thrombocyte
Platelets
Blood clotting/preventing blood loss
Hematopoiesis
Production of blood cells
Occurs in red bone marrow (kids- RBM everywhere but adults- RBM only in certain bones)
All blood cells come from hematopoietic stem cell
In a single day, marrow creates around 100 billion new cells
Hematopoietic stem cell
Become committed to forming a certain type of blood cell
Once committed, the cell cannot become another type of cell
Erythrocytes (expanded)
Blood cell type responsible for respiratory gas transport
Nuclei and organelles removed during cell development for more ability to carry oxygen through hemoglobin
What is the advantage to having no nuclei or organelles?
Creating more space for hemoglobin which increases oxygen carrying capacity
Hemoglobin
Protein responsible for O2 transport in blood (molecule)
composed of heme pigment bound to globin protein
Globin Protein
2 alpha chains, 2 beta chains
Each chain binds to 1 heme group
Heme Group
Fe+ ion at center
Fe+ can bind one molecule O2
4 O2’s can bind to a single hemoglobin
Hemoglobin binds and breaks from oxygen very easily
Important- so we can take in as much oxygen as we can for all our body tissues
Will be unloaded very easily so our tissue cells have access
If it was more difficult, it would have lower than normal oxygen levels
Other features that make erythrocytes ideal for gas exchange
- Large surface area relative to volume (increased surface area = increased diffusion rate of O2)
- Flattened disc-shape (Flat shape = increased diffusion rate of O2)
- Anaerobic mechanism of energy production (RBC don’t use any of the oxygen that thy carry, maximizes O2 to tissue cells)
Erythropoiesis
The production of red blood cells
Hematopoietic stem cell “commits” to a proerythroblast
Tightly regulated process to keep the balance
Hypoxia
Too few erythrocytes
Not enough hemoglobin to reach the body tissues
Lead to cell and tissue death, can be reversed as long as you can get oxygen there
Too many erythrocytes
too viscous and slow down oxygen delivery in the blood vessels
Hormonal Controls of erythropoiesis
Erythropoietin
Testosterone
Erythropoietin
Hormone control
Stimulates erythrocyte production
Small amounts almost always present in the blood to set the basal rate of production
What causes an increase in EPO release?
Negative feedback mechanism- Excessive oxygen supply
Testosterone
Enhances the production of EPO
Males generally have more erythrocytes and Hemoglobin than females
Dietary needs for normal erythrocyte production
General nutrients
B-complex vitamins
Iron
General Nutrients for normal erythrocyte production
Amino acids
Lipids
carbohydrates for cell synthesis
B complex vitamins
B12 and folic acid (B9)
Necessary for normal DNA synthesis
Red blood cells can get rid of nucleus and DNA but before that it will direct normal cellular development
Iron
Normal Hb synthesis
65% of body’s iron supply is in Hb
Other 35% remains stores in the liver, spleen, etc.
“Free” iron bound to protein transferrin (erythrocyte takes up iron as needed)
Transferrin
Toxic and can impair normal cellular function in the body
Detroying Erythrocytes
Average lifespan- 120 daysish
Hb begins to degenerate, cell becomes less flexible and can’t go to many places
Macrophages engulf and destroy cell where
1. heme group splits from globin and
2. Iron bound to transport protein and saves for reuse in the liver
Bilirubin
Heme group broken down into this in the liver and go to the intestines in bile –> feces
Globin is broken down into amino acids and released to circulation
Anemia
Insufficient oxygen supply to meet body needs
Symptoms- Paleness, cold, short-of-breath, third
Causes hypoxis and and indicator of a larger problem
Anemia is caused by…
- Blood loss
- Inadequate erythrocyte production
- Excessive erythrocyte destruction/deformation
Acute hemorrhagic anemia
Severe, sqift blood loss
Chronic Hemorrhagic anemia
Slow, persistent blood loss (ulcer bleeding, hemorrhoids)
Inadequate erythrocyte production example
iron-deficiency anemia
(nutritional origins), renal anemia (little/no EPO release - kidneys)
Excessive erythrocyte destruction/deformation example
Sickle Cell Anemia (beta chains deformed and don’t bind as readily and will have hooks that will make RBC’s clump together and inhibit blood circulation)