Biology Chapter on Blood and Circulation

Study Notes

Blood

Composition: Blood consists of:
- Plasma: Liquid component (about 55% of blood volume); contains water, electrolytes, proteins, hormones, and waste.
- Formed Elements: Cells and cell fragments (about 45% of blood volume):
  - Red blood cells (erythrocytes): Carry oxygen via hemoglobin.
  - White blood cells (leukocytes): Immune response; types include lymphocytes, neutrophils, monocytes, eosinophils, and basophils.
  - Platelets (thrombocytes): Cell fragments involved in blood clotting.
Functions:
- Transport: Delivers oxygen and nutrients to cells; removes carbon dioxide and waste.
- Regulation: Maintains body temperature, pH levels, and fluid balance.
- Protection: Immune response (WBCs) and hemostasis (platelets).

Circulation

Circulatory System Components:
- Heart: Muscular organ that pumps blood.
- Blood Vessels:
  - Arteries: Carry oxygen-rich blood away from the heart.
  - Veins: Return oxygen-poor blood to the heart.
  - Capillaries: Microscopic vessels where gas and nutrient exchange occurs.
Types of Circulation:
- Systemic Circulation:
  - Delivers oxygenated blood from the left side of the heart to the rest of the body and returns deoxygenated blood to the right side of the heart.
- Pulmonary Circulation:
  - Transports deoxygenated blood from the right side of the heart to the lungs for oxygenation and then returns oxygen-rich blood to the left side of the heart.
Cardiac Cycle:
- Comprises the sequence of contraction (systole) and relaxation (diastole) of the heart.
- Blood flows from the atria to the ventricles and then out to the arteries.
Regulation of Blood Pressure:
- Determined by cardiac output and peripheral resistance.
- Controlled by neural and hormonal mechanisms, including the autonomic nervous system and hormones like adrenaline and angiotensin.
Common Disorders:
- Anemia: Low red blood cell count or hemoglobin.
- Thrombosis: Blood clots obstructing blood flow.
- Hypertension: High blood pressure; risk factor for heart disease and stroke.
- Heart failure: Inability of the heart to pump effectively.

Blood Composition

Blood is composed of plasma and formed elements.
Plasma is the liquid component, making up 55% of blood volume. It contains water, electrolytes, proteins, hormones, and waste products.
Formed elements consist of cells and cell fragments, comprising about 45% of blood volume.
Red blood cells (erythrocytes) carry oxygen via hemoglobin.
White blood cells (leukocytes) are crucial for the immune response and include different types like lymphocytes, neutrophils, monocytes, eosinophils, and basophils.
Platelets (thrombocytes) are cell fragments responsible for blood clotting.

Blood Functions

Blood transports oxygen and nutrients to cells and removes carbon dioxide and waste products.
It regulates body temperature, pH levels, and fluid balance.
Blood protects the body through the immune response (white blood cells) and hemostasis (platelets).

Circulatory System Components

The heart is a muscular organ responsible for pumping blood.
Blood vessels transport blood:
- Arteries carry oxygen-rich blood away from the heart.
- Veins return oxygen-poor blood to the heart.
- Capillaries are microscopic vessels where gas and nutrient exchange occurs between the blood and tissues.

Types of Circulation

Systemic Circulation: Delivers oxygenated blood from the left side of the heart to the body and returns deoxygenated blood to the right side of the heart.
Pulmonary Circulation: Transports deoxygenated blood from the right ventricle to the lungs for oxygenation, then returns oxygenated blood to the left atrium.

Cardiac Cycle

The cardiac cycle involves the sequential contraction (systole) and relaxation (diastole) of heart chambers.
Blood flow during the cycle: from the atria to the ventricles, and then out to the arteries.

Regulation of Blood Pressure

Blood pressure depends on cardiac output (the amount of blood pumped by the heart per minute) and peripheral resistance (the resistance to blood flow in the arteries).
Neural and hormonal mechanisms like the autonomic nervous system, adrenaline, and angiotensin regulate blood pressure.

Common Blood Disorders

Anemia: Condition characterized by low red blood cell count or hemoglobin levels.
Thrombosis: Formation of blood clots that obstruct blood flow, potentially leading to serious health complications.
Hypertension: High blood pressure, a major risk factor for heart disease and stroke.
Heart failure: The heart's inability to pump blood effectively, resulting in inadequate blood circulation.

Description

Explore the essential components and functions of blood along with the circulatory system. This quiz covers the makeup of blood, including plasma and formed elements, and the roles they play in maintaining health. Test your knowledge on how blood circulates through the body, its functions, and the structures involved in circulation.