Chapter 17- Blood Flashcards
What are the 3 main functions of blood?
- Transport
- Maintenance/regulation
- Protection
What substances does blood transport (3)?
- Oxygen and nutrient delivery to tissues
- Waste removal from tissues (carbon dioxide and nitrogenous cellular waste)
- Hormone transport to target organs
What variables does blood regulate? (3)
- Body temperature
- pH
- Fluid volume
How does blood regulate body temperature?
Blood is mostly water, and water can absorb heat and set the body temperature. Blood can increase or decrease heat also. Blood can be moved closer to or further away from the skin. Blood that is closer to the skin will give off heat.
Why is it important for pH to be regulated?
pH must stay within its specific range or chemical reactions and cellular functions will be disrupted
Why is it important for fluid volume to be regulated?
High fluid volume will make your heart work harder, as will low fluid volume- blood must be transported through the body and blood pressure must be maintained.
What does blood protect against (2)?
- Blood loss- platelets clot blood when blood vessels are damaged
- Infection- leukocytes monitor for pathogens
Characteristics of blood (4)
- Scarlet to dark red in color, depends on how much oxygen is bound in the red blood cells
- Typical metallic taste due to iron
- pH range: 7.35-7.45
- Viscous- thicker than water due to erythrocyte composition
What are the 2 main components of blood?
Plasma and blood cells
Blood plasma function
Transports solutes and suspends the living portion of blood
Blood plasma composition
90% water, contains many kinds of solutes
What types of solutes are present in blood plasma? (6)
- Electrolytes
- Nitrogenous substances (urea, uric acid, etc.)
- Organic nutrients (glucose, amino acids, triglycerides, etc.).
- Respiratory gasses- carbon dioxide mainly
- Hormones- don’t enter any cells
- Plasma proteins
Plasma proteins
This solute makes up most of the mass of blood plasma. They float freely in the plasma, but are not used by cells for energy or nutrients- function varies depending on the protein. One important type of plasma protein is albumin.
Where are plasma proteins mainly produced?
The liver
Albumin
Plasma protein that is the major transport protein of blood, contributes to osmotic pressure in capillaries. If you didn’t have albumin, you would lose osmotic pressure.
What would happen to the bloodstream if you didn’t produce albumin?
A huge amount of water would leave the bloodstream. This is very bad- most of plasma is water, so the heart wouldn’t have much left to pump, it needs water in addition to cells. Water rushes into surrounding body tissues, causing extreme bloating and physically separating cells from each other, disrupting cellular functions because nutrients have a hard time getting to cells
Osmotic pressure
Osmotic pressure is the measure of the tendency for water to move into a concentrated solution (from the tissues to the blood, for example).
Types of blood cells (3)
Erythrocytes, leukocytes, platelets. Leukocytes are the only “true” cells since platelets are cell fragments and erythrocytes don’t have organelles.
All blood cells are
Short lived and non-mitotic- formed by hematopoietic stem cell, so mature cells do not reproduce
What is hematocrit? What are the normal ranges for males and females?
The portion of total blood volume made up by erythrocytes. Males- 47%, females- 42%
Hematopoiesis definition
A general term for production of all 3 blood cell types
Where does hematopoiesis occur?
Red bone marrow tissue.
How does hematopoiesis occur?
All blood cells arise from hematopoietic stem cells in the bone marrow. 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, the marrow creates about 100 billion new cells. The spleen and liver also destroy a large amount of blood cells every day. This is a balancing act, we don’t want blood to be too thick (have too many cells) or too thin.
Where is red bone marrow located?
In adults, the axial skeleton, girdles, and heads of femur and humerus. In children, most bones have red bone marrow until they stop growing (18-21).