Physiology Ch. 2 Blood

Study Notes

Blood is a liquid connective tissue that circulates through blood vessels, powered by the heart's pumping action.

Transportation:
- Carries nutrients (amino acids, lipids, glucose), hormones, and oxygen to cells.
- Transports waste products and carbon dioxide away from cells.
Regulation:
- pH buffering (7.35-7.45): Maintains proper acidity levels, involving hydrogen and bicarbonate ions.
- Body temperature regulation: Water and vasodilation of surface vessels help regulate heat.
Protection:
- Clot formation: Minimizes blood loss when a blood vessel is damaged.
- Protection against foreign substances: Antibodies and white blood cells (WBCs) defend against pathogens.

Cellular portion (formed elements):
- Composed of red blood cells (RBCs), white blood cells (WBCs), and platelets.
- Majority are red blood cells.
- Platelets are necessary for blood clotting.
- Buffy coat is the layer between RBC's and Plasma (WBC's and platelets)
Fluid portion (plasma):
- Mostly water (91-92%).
- Contains dissolved proteins (albumin, globulins, fibrinogen) and other solutes (electrolytes, nutrients, gases, waste).
Plasma makes up roughly 55% of blood volume
The average adult has roughly 5 liters of blood with about 2.7-3.0 Liters of blood plasma.

Plasma:
- Mostly water (91-92%)
- Contains dissolved proteins (albumin, globulins, fibrinogen) and other solutes (electrolytes, nutrients, gases, waste).
Erythrocytes (red blood cells):
- 1000-fold more RBC's than WBCs
- Flat, bi-concave discs without a nucleus.
- Responsible for oxygen transport.
- Shape increases surface area to maximize oxygen absorption and diffusion. -Contain hemoglobin for oxygen transport. -Derived from bone marrow precursors. -Have a lifespan of 70-120 days.
Leukocytes (white blood cells):
- Variety of types with distinct roles in the immune response.
- Larger than RBCs
- Contain nuclei and mitochondria.
- Can move and fight infection in a particular region of the body.
- Lifespan of 13-20 days
Thrombocytes (platelets):
- Cellular fragments involved in blood clotting.
- Irregular shape and derived from bone marrow megakaryocytes.
- Contain clotting factors.
- Short lifespan (7-14 days)

Number: 4.6-6.2 million/mm³ in males and 4.5-5.1 million/mm³ in females.
Shape: Biconcave discs for increased surface area and flexibility for passing through capillaries.
Size: About 7.5 µm in diameter.
Functions:
- Transport oxygen from lungs to tissues.
- Transport carbon dioxide from tissues to lungs.
- Buffering to maintain acid-base balance
Production:
- Occurs in the red bone marrow.
- Maturation from precursors takes approximately 4-5 days.
- Stimulated by erythropoietin produced in the kidney.
- Requires factors like Vitamin B12 and folic acid.

Contain a nucleus containing mitochondrial DNA
Contain varied lifespans
Involved in providing an immune response
Respond to foreign invaders like bacteria, viruses, etc
Types of Leukocytes:
- Neutrophils, Eosinophils, Basophils
- Monocytes, Lymphocytes
The lifespan is 13 to 20 days.
Some are formed partially in the bone marrow and partially in lymphatic tissue.

Anemia: Low red blood cell count or hemoglobin level.
Polycythemia: High red blood cell count.
Clinical Assessments: -Mucous membrane color (Pink/blue)
Capillary refill time (CRT) to assess perfusion(2 seconds or less is normal CRT)