Chapter 17 Blood Flashcards
What are the three blood functions?
- Transport
- Maintenance
- Protection
Blood functions
Transport
- Oxygen and nutrient delivery to tissues (glucose, amino acids, lipids, etc)
- Waste removal from tissues (CO2)
- hormone transport to target organs (hormones go directly to bloodstream)
Blood functions
Maintenance
- body temperature (any fluid body produces will be mostly water and water absorbs heat)
- pH (buffer- reduced bug changes in blood)
- Fluid volume
Blood functions
Protection
- blood clotting (cutting, scraping skin)
- infection (immune system function, WBC)
Characteristics of blood
- Scarlett to dark red in color (color is determined by how much oxygen is present)
- brighter red= more oxygen blood
- dark red=less oxygen blood
- Total amount= 5.25 L
- pH range= 7.35-7.45
- Viscous due to erythrocytes (blood is thicker than water)
- Erythrocytes are RBCs- more RBCs in blood means the blood will be more thicker
Blood composition: plasma and blood cells
Blood plasma
- fluid (non-living) portion of blood
- Composition is 90% water and 6 solutes found in plasma
1. Electrolytes Greatest amount
2. Nitrogenous substances (urea, uric acid, etc)
3. Organic nutrients (glucose, amino acids, triglycerides, etc)
4. Respiratory gases (oxygen and carbon dioxide)
5. Hormones
6. Plasma proteins most of mass (produced by liver)
Plasma proteins
What are the several types of plasma proteins
- Albumin
- Fibrinogen
- Globulins
Plasma protein
Albumin
- Major transport protein of blood and contributes to osmotic pressure in capillaries (antibodies)
plasma protein
Fibrinogen
- soluble protein that functions in blood clotting
- blood is only fluid tissue, you cannot see fibrinogen bc it is dissolved in blood–> you can only see it in an injury
plasma protein
globulins
- Transport proteins, antibodies (immune defense) etc
- contributes to osmotic pressure in our capillaries
blood cells
- All blood cells are short lived and non mitotic
- red bone marrow pumps out blood cells to keep up with what you are losing
- three types of blood cells
What are the three types of blood cells
- Erythrocytes
-Red blood cells
-Hematocrit: portion of total blood volume made up by erythrocytes
-males: -47%
-females: - 42% - leukocytes (White blood cells)
- Thrombocyte (platelets) important for blood clotting
Hematopoiesis
- Production of blood cells (all 3 types)
- occurs only in red bone marrow
- all blood cells arise from Hematopoietic stem cell (stem cell can become anything at first)
- Hematopoietic stem cells eventually become “committed” to forming a certain type of blood cell
- Once committed, the cell cannot become any other cell type
- In a single day-marrow creates- 100 billion new cells
Erythrocytes (RBCS)
Erythrocytes
- blood cell type responsible for respiratory gas transport
- Nuclei and organelles removed during cell development (makes more room for extra hemoglobin)
Erythrocytes
Hemoglobin (Hb)
- Protein responsible for O2 transport in blood
- hemoglobin composed of heme pigment bound to globin protein
- globin protein has 2 alpha chains, 2 beta chains
- each chain binds to 1 heme group
- each heme group has Fe+ ion at center
- Each Fe+ can bind one molecule O2
- Hb binds and breaks free of oxygen very easily
Erythrocytes
Why are Erythrocytes are ideal for gas exchange
- large surface area relative to volume (to bring or leave smth in cell, you need to go through the plasma membrane. The more plasma membrane then it is easier to cross)
- Flattened disc shape
- Anaerobic mechanism of energy production (RBCS do not use any of the oxygen then carry-no oxygen wasted by the RBCs. RBCs are gonna use glycolysis to produce any ATP they need)
Erythropoiesis
- Erythropoiesis: The production of red blood cells
- Hematopoietic stem cell “commits” to a Proerythroblast
- Tightly regulated process
- When there are too few erythrocytes it is known as Hypoxia
- too many erythrocytes leads to cardiovascular issues and it is hard to pump blood
Erythropoiesis (hormonal controls)
Erythropoietin (EPO)
- EPO: stimulates erythrocyte Production
- produced and released by kidneys
- kidneys have a baseline of how much EPO they produce, if kidney cells become hypoxic (short on oxygen) it stimulates EPO release
- EPO only stimulates cells already committed to becoming erythrocytes
- Small amount almost always present in blood to set basal rate production
- (-) feedback mechanism: excessive oxygen supply suppresses EPO release
- directly stimulates
Erythropoiesis (hormonal controls)
Testosterone
- enhances production of EPO
- males generally have more erythrocytes and Hb than females
- indirectly
- more testosterone–> more EPO
Erythropoiesis
Dietary needs for normal erythrocyte production:
- General nutrients: amino acids, lipids, carbohydrates necessary for cell synthesis
- B-complex vitamins: B12 and folic acid
-Necessary for normal DNA synthesis - Iron: Normal Hb synthesis
-65% of bodys iron supply is in Hb (hemoglobin)
-Remainder stored in liver, spleen, etc
-“free” Iron bound to protein transferrin- erythrocyte takes up Iron as needed
Destroying Erythrocytes
- Average lifespan: 120 days
-Hb begins to degenerate, cell becomes less flexible - Macrophages engulf and destroy cell
-heme group splits free from globin protein
-heme broken down to bilirubin in the liver and excreted to intestines in bile–>leaves body in feces
-Heme cannot be reused
-Globin broken down to amino acids, released to circulation - Fe2+ bound to transport protein and saved for reuse
Homeostatic imbalances of Erythrocytes
Anemia
- insufficient oxygen supply to meet body needs
- Symptoms: paleness, old, short of breath, tired
Homeostatic imbalances of Erythrocytes
What is anemia caused by?
1. blood loss
-acute hemorrhagic anemia: severe, swift blood loss
-chronic hemorrhagic anemia: slow, persistent blood loss
2. Inadequate erythrocyte production
-Example: iron deficiency anemia (nutritional origins), renal anemia (little/no EPO release)
3. Excessive erythrocyte destruction/deformation
-sickle cell anemia
Homeostatic Imbalances of Erythrocytes
Polycythemia
- increase in number of erythrocytes
- icrease viscosity (thickness)
what are the three types of polycythemia?
- Polycythemia vera
- secondary polycythemia
- Blood doping