Blood Physiology Overview

Systems Physiology

Definition: Study of the functions of organ systems and their interactions.
Major Systems:
1. Nervous System:
  - Controls body activities through electrical signals.
  - Central nervous system (CNS) and peripheral nervous system (PNS).
2. Endocrine System:
  - Regulates bodily functions through hormones.
  - Includes glands like the pituitary, thyroid, and adrenal glands.
3. Cardiovascular System:
  - Transports nutrients, gases, hormones, and waste products.
  - Composed of the heart, blood vessels, and blood.
4. Respiratory System:
  - Facilitates gas exchange (O2 and CO2) in the lungs.
  - Composed of airways, lungs, and respiratory muscles.
5. Digestive System:
  - Breaks down food and absorbs nutrients.
  - Composed of the gastrointestinal tract and accessory organs.
6. Musculoskeletal System:
  - Provides structure, support, and movement.
  - Consists of bones, muscles, and connective tissues.
7. Immune System:
  - Defends against pathogens and disease.
  - Composed of lymphatic organs, cells, and antibodies.
8. Urinary System:
  - Regulates fluid balance and removes waste products.
  - Includes kidneys, ureters, bladder, and urethra.
9. Reproductive System:
  - Responsible for producing offspring.
  - Includes male and female reproductive organs.
Homeostasis:
- The maintenance of stable internal conditions despite external changes.
- Involves feedback mechanisms (positive and negative) to regulate physiological processes.

Blood Physiology

Composition:
- Plasma (55% of blood volume):
  - Liquid component containing water, electrolytes, proteins, hormones, and waste products.
- Formed Elements (45% of blood volume):
  - Red blood cells (erythrocytes): Carry oxygen via hemoglobin.
  - White blood cells (leukocytes): Key players in the immune response.
  - Platelets (thrombocytes): Involved in blood clotting.
Functions:
1. Transportation:
  - Oxygen and carbon dioxide between lungs and tissues.
  - Nutrients from the digestive tract to cells.
  - Hormones from glands to target organs.
  - Waste products to excretory organs.
2. Regulation:
  - Maintains pH balance through buffers.
  - Regulates body temperature via blood flow adjustments.
  - Maintains fluid balance and electrolyte levels.
3. Protection:
  - Immune defense against pathogens.
  - Clot formation to prevent blood loss.
Hemostasis:
- The process stopping bleeding, involves:
  - Vascular spasm: Narrowing of blood vessels.
  - Platelet plug formation: Platelets adhere to damaged area.
  - Coagulation: Blood clotting cascade resulting in fibrin formation.
Blood Types:
- Determined by the presence of antigens (A, B, Rh factor).
- Major types: A, B, AB, O, with each type having Rh+ or Rh- variations.
Hemoglobin:
- Protein in red blood cells that binds and transports oxygen.
- Monitors oxygen levels in blood; crucial for cellular respiration.

These notes provide an overview of systems physiology and blood physiology, focusing on essential concepts and functions.

Systems Physiology

Study of organ systems' functions and their interactions within the body.
Nervous System:
- Controls activities via electrical signals.
- Divided into Central Nervous System (CNS) and Peripheral Nervous System (PNS).
Endocrine System:
- Regulates functions through hormones released by glands.
- Major glands include the pituitary, thyroid, and adrenal glands.
Cardiovascular System:
- Transports nutrients, gases, hormones, and waste products.
- Comprised of the heart, blood vessels, and blood.
Respiratory System:
- Facilitates gas exchange (oxygen and carbon dioxide) in the lungs.
- Involves airways, lungs, and respiratory muscles.
Digestive System:
- Breaks down food to absorb nutrients.
- Consists of the gastrointestinal tract and accessory organs.
Musculoskeletal System:
- Provides structure, support, and movement.
- Made up of bones, muscles, and connective tissues.
Immune System:
- Defends against pathogens and diseases.
- Includes lymphatic organs, immune cells, and antibodies.
Urinary System:
- Regulates fluid balance and removes waste products.
- Comprises kidneys, ureters, bladder, and urethra.
Reproductive System:
- Responsible for offspring production.
- Encompasses male and female reproductive organs.
Homeostasis:
- Maintenance of stable internal conditions despite external changes.
- Involves feedback mechanisms, both positive and negative, to regulate bodily functions.

Blood Physiology

Composition of Blood:
- Plasma: Accounts for 55% of blood volume. Contains water, electrolytes, proteins, hormones, and waste products.
- Formed Elements: Make up 45% of blood volume.
  - Red blood cells (erythrocytes): Transport oxygen via hemoglobin.
  - White blood cells (leukocytes): Essential for immune response.
  - Platelets (thrombocytes): Play a critical role in blood clotting.
Functions of Blood:
- Transportation:
  - Oxygen and carbon dioxide transport between lungs and tissues.
  - Nutrient transport from the digestive tract to cells.
  - Hormone distribution from glands to their target organs.
  - Waste product removal to excretory organs.
- Regulation:
  - Maintains pH balance through buffering systems.
  - Regulates body temperature by adjusting blood flow.
  - Maintains fluid balance and electrolyte levels.
- Protection:
  - Immune defense through leukocytes against pathogens.
  - Clot formation via platelets to prevent blood loss.
Hemostasis:
- Process that stops bleeding involving several steps:
  - Vascular spasm: Immediate narrowing of blood vessels at injury site.
  - Platelet plug formation: Platelets adhere to the damaged area.
  - Coagulation: Cascade of events leading to fibrin formation and clotting.
Blood Types:
- Determined by antigens present: A, B, and Rh factor.
- Major blood types include A, B, AB, and O, with Rh+ and Rh- variations.
Hemoglobin:
- A protein in erythrocytes that binds and transports oxygen.
- Crucial for monitoring oxygen levels in blood, essential for cellular respiration.