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Aug 30, 2020 · The pH of blood averages about 7.4; however, it can range from 7.35 to 7.45 in a healthy person. Blood is therefore somewhat more basic (alkaline) on a chemical scale than pure water, which has a pH of 7.0. Blood contains numerous buffers that actually help to regulate pH. Blood constitutes approximately 8 percent of adult body weight.
- Blood
- Regulation of Blood Cell Production
- Design of Cardiovascular System
- Heart Anatomy
- Vascular System
- Lymphatic System
- Mechanism of Lymph Flow
- Regulation of Systemic Arterial Pressure
- Hemorrhage and Other Causes of Hypotension
- Shock
Blood is composed of a liquid, plasma,and blood cells such as erythrocytes (red blood cells,) leukocytes (white blood cells), and platelets (cell fragments). Hematocrit is the percentage of blood volume occupied by the erythrocytes.
In children, the marrow of most bones produces blood cells whereas in adults only the bones of the upper body produce blood cells. All blood cells descend from a single population of bone marrow cells called pluripotent hematopoietic stem cells. These cells can divide into (1) pluripotent stem cells, (2) lymphoid stem cells that give rise to lympho...
Rapid blood flow in one direction is called bulk flow. This is produced by pumping action of the heart. The high branching of blood vessels ensures the proximity of all cells to some capillaries. Nutrients and metabolic end products move between capillary blood and interstitial fluid by diffusion. The heart is longitudinally divided into 2 halves: ...
The heart is a muscle enclosed in a sac called the pericardium. The walls of the heart are composed of cardiac muscle cells called myocardium. A thin layer of cells called endothelial cells lines the inner surface. Located between the atrium and ventricle on each side are the atrioventricular (AV) valves. The right AV valve is called the tricuspid ...
Arteries
The arteries are large, elastic tubes lined at the interior by the endothelial cells. Arterial walls have connective tissue and smooth muscles. During systole, contraction of ventricles ejects blood into arteries, distending the arterial walls. During diastole, the walls recoil passively and more blood is driven out. There is always some blood in the arteries to keep them semi-inflated. Maximum arterial pressure reached during systole is called systolic pressure (SP), and minimum arterial pre...
Arterioles
The arterioles contain smooth muscles that can relax to increase vessel radius (vasodilation) or contract to decrease vessel radius (vasoconstriction). It controls blood flow through an organ. This can be calculated with this formula: Forgan = MAP / Resistanceorgan Local controls. Local controls are mechanisms independent of hormones and nerves. Hyperemia occurs when the blood flow in an organ increases by arteriolar dilation in response to an increase in metabolic activity that causes local...
Capillaries
Capillaries permeate every tissue in the body to provide front line access to cells in order to exchange nutrients and metabolic end products. Anatomy of the Capillary Network. A capillary is a thin-walled tube of endothelial cells one layer thick resting on a basement membrane without any surrounding muscle or elastic tissue. The endothelial cells are separated from each other by narrow, water-filled spaces called intercellular clefts. The velocity of Capillary Blood Flow. Blood velocity dec...
The lymphatic system is a network of small organs (lymph nodes) and tubes (lymphatic vessels) through which lymph flows. Lymph is a fluid derived from the interstitial fluid. Lymphatic capillaries are composed of a single layer of endothelial cells resting on a basement membrane. Their water channels are permeable to all interstitial fluid componen...
Lymph is propelled by the rhythmical contractions of smooth muscle lining the walls of lymphatic vessels. The contractions are triggered by the stretching of the walls when lymph enters the system. Lymphatic vessels have valves to produce a one-way flow. The vessels are innervated by sympathetic neurons and are also influenced by the skeletal muscl...
Mean arterial pressure is determined by cardiac output and total peripheral resistance (TPR). TPR is the sum of resistance to flow offered by all systemic blood vessels. MAP = CO x TPR Arteriolar resistance is the main determinant of TPR. Any deviation in MAP elicits homeostatic reflexes so that CO or TPR is changed to minimize the deviation.
Hypotension is low blood pressure due to low blood volume. SV, CO, MAP decrease as a direct result of hemorrhage and arterial baroreceptor reflexes work to restore them to normal. HR and TPR increase as reflex responses due to increases in sympathetic outflow. Interstitial fluid is moved into the vascular system due to reduced capillary pressure. I...
Tissue or organ damage due to reduced blood flow is called shock. 1. Hypovolemic shock is caused by a decrease in blood volume due to hemorrhage or loss of fluid 2. Low-resistance shock is due to a decrease in TPR due to excessive release of vasodilators, as in allergy and infection 3. Cardiogenic shock due to a decrease in CO (cardiac output), as ...
Red blood cells (also called erythrocytes) make up about 40% of the blood's volume. Red blood cells contain hemoglobin, a protein that gives blood its red color and enables it to carry oxygen from the lungs and deliver it to all body tissues. Oxygen is used by cells to produce energy that the body needs, leaving carbon dioxide as a waste product.
- Ravindra Sarode
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Nov 23, 2024 · The components of blood include plasma (the liquid portion, which contains water, proteins, salts, lipids, and glucose ), red blood cells and white blood cells, and cell fragments called platelets. Figure \(\PageIndex{1}\): Components of human blood: The cells and cellular components of human blood are shown.
Recall that blood is a connective tissue. Like all connective tissues, it is made up of cellular elements and an extracellular matrix. The cellular elements—referred to as the cellular components or formed elements—include red blood cells (RBCs), white blood cells (WBCs), and cell fragments called platelets.
It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma (Figure 18.2). Because the heaviest elements in blood are the erythrocytes, these settle at the very bottom of the hematocrit tube.
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Jun 16, 2020 · Specific components of the blood include red blood cells, white blood cells, platelets, and the plasma, which contains coagulation factors and serum. Blood is important for regulation of the body’s pH, temperature, osmotic pressure, the circulation of nutrients and removal of waste, the distribution of hormones from endocrine glands, and the elimination of excess heat; it also contains ...
