Chapter 12
Chapter 12: Cardiovascular System
12.1
3 types of blood vessels * Arteries: carry blood away from the heart to the capillaries * Capillaries: permit exchange of material with the tissues * Veins: return blood from the capillaries to the heart.
Arteries
Wall has 3 layers * Endothelium: inner layer, made up of simple squamous epithelium, with a connective tissue basement membrane that has elastic fibers. * Middle layer: thickest later and consists of smooth muscle that can contract to regulate blood flow and blood presser. * Outer layer: fibrous connective tissue near the middle layer, but it becomes loose connective tissue at its periphery.
Aorta: largest artery in the human body * Carries 0 rich blood from the heart to other body parts. * Smaller arteries branch off from the aorta, forming a large number of arterioles.
Arterioles: small arteries just visible to the naked eye. * Inner layer: endothelium * Middle layer: elastic tissue and fibers that encircle the arteriole.
When the muscle fibers are contracted, the vessels diameter becomes smaller.
When the muscle fibers are relaxed, the vessels diameter becomes larger.
The Capillaries * Join arterioles to venules * Walls are composed of single layers of endothelium with a basement membrane. * Total surface area in the body is about 6,000 square meters. * Cornea of the eye, is capillary free
Homeostasis in capillaries * Oxygen and nutrients, such as glucose diffuse out of a capillary into the tissue fluid that surrounds cells. * Wastes, such as carbon dioxide, diffuse into the capillaries. * Any excess is picked up by the lymphatic vessels.
The Veins * Take blood from the capillary beds to the heart
Venules: small veins * Venules drain blood from the capillaries and then join to form a vein
Have the same 3 layers as arteries do
Valves: allow flood to flow only toward the heart and open and prevent blood
12.1
3 types of blood vessels * Arteries: carry blood away from the heart to the capillaries * Capillaries: permit exchange of material with the tissues * Veins: return blood from the capillaries to the heart.
Arteries
Wall has 3 layers * Endothelium: inner layer, made up of simple squamous epithelium, with a connective tissue basement membrane that has elastic fibers. * Middle layer: thickest later and consists of smooth muscle that can contract to regulate blood flow and blood presser. * Outer layer: fibrous connective tissue near the middle layer, but it becomes loose connective tissue at its periphery.
Aorta: largest artery in the human body * Carries 0 rich blood from the heart to other body parts. * Smaller arteries branch off from the aorta, forming a large number of arterioles.
Arterioles: small arteries just visible to the naked eye. * Inner layer: endothelium * Middle layer: elastic tissue and fibers that encircle the arteriole.
When the muscle fibers are contracted, the vessels diameter becomes smaller.
When the muscle fibers are relaxed, the vessels diameter becomes larger.
The Capillaries * Join arterioles to venules * Walls are composed of single layers of endothelium with a basement membrane. * Total surface area in the body is about 6,000 square meters. * Cornea of the eye, is capillary free
Homeostasis in capillaries * Oxygen and nutrients, such as glucose diffuse out of a capillary into the tissue fluid that surrounds cells. * Wastes, such as carbon dioxide, diffuse into the capillaries. * Any excess is picked up by the lymphatic vessels.
The Veins * Take blood from the capillary beds to the heart
Venules: small veins * Venules drain blood from the capillaries and then join to form a vein
Have the same 3 layers as arteries do
Valves: allow flood to flow only toward the heart and open and prevent blood