The Cardiovascular System: Blood Vessels

Flashcards covering key vocabulary and concepts from the lecture on the cardiovascular system and blood vessels, including vessel types, layers, blood flow dynamics, and blood pressure regulation.

Arteries

Blood vessels that carry blood away from the heart.

Pulmonary Arteries

The exception to oxygenated arteries, as they carry deoxygenated blood from the heart to the lungs.

Veins

Blood vessels that carry blood towards the heart.

Pulmonary Veins

The exception to deoxygenated veins, as they carry oxygenated blood from the lungs to the heart.

Tunica Intima

The innermost layer of blood vessel walls, composed of endothelium.

Tunica Media

The middle layer of blood vessel walls, composed of smooth muscle and elastic fibers, typically thicker in arteries.

Tunica Externa (Tunica Adventitia)

The outermost layer of blood vessel walls, composed of connective tissue.

Elastic Arteries (Conducting Arteries)

Large, thick-walled arteries near the heart that contain abundant elastic tissue to absorb pressure changes.

Muscular Arteries (Distributing Arteries)

Arteries distal to elastic arteries that deliver blood to specific organs; have a thick tunica media with more smooth muscle.

Arterioles

Smallest arteries, leading to capillary beds; play a key role in controlling blood flow into capillaries.

Continuous Capillaries

Most common capillaries, with an uninterrupted endothelial lining; found in skin, muscles, and nervous system.

Fenestrated Capillaries

Capillaries with pores (fenestrations) in their endothelial cells, allowing greater permeability; found in kidneys, small intestine, and endocrine glands.

Sinusoid Capillaries (Sinusoids)

Highly leaky capillaries with large lumens and large intercellular clefts, allowing passage of large molecules and cells; found in liver, bone marrow, and spleen.

Precapillary Sphincters

Rings of smooth muscle that control blood flow into capillary beds, ensuring blood distribution matches tissue needs.

Venous Adaptations for Blood Return

Special structures in veins such as large lumens, venous valves, and the muscular and respiratory pumps, which ensure blood returns to the heart.

Peripheral Resistance

The opposition to blood flow due to friction between blood and vessel walls; influenced by blood viscosity, vessel length, and most significantly, vessel diameter.

Systemic Pressure (Greatest)

Blood pressure is greatest in the aorta, nearest to the heart's pumping action.

Systolic Pressure

The peak arterial pressure reached during ventricular contraction.

Diastolic Pressure

The lowest arterial pressure reached during ventricular relaxation.

Pulse Pressure

The difference between systolic and diastolic pressure (Systolic Pressure - Diastolic Pressure).

Mean Arterial Pressure (MAP)

The average pressure propelling blood to the tissues, calculated as Diastolic Pressure + 1/3 Pulse Pressure.

Factors Aiding Venous Return

Include the muscular pump, respiratory pump, venoconstriction, and venous valves.

Main Factors Influencing Blood Pressure

Cardiac output (CO), peripheral resistance (PR), and blood volume.

Increasing Cardiac Output

Achieved by increasing heart rate or stroke volume, often influenced by sympathetic activity or increased venous return.

Neural Blood Pressure Control

Involves the cardiovascular center in the medulla oblongata, sympathetic and parasympathetic nervous systems, and sensory inputs from baroreceptors and chemoreceptors.

Vasomotor Center

A cluster of sympathetic neurons in the medulla oblongata that regulates blood vessel diameter and therefore blood pressure.

Baroreceptor Locations

Located in the carotid sinuses, aortic arch, and walls of large arteries of the neck and thorax, detecting changes in arterial pressure.

Baroreceptor Reflexes

Initiated by baroreceptors to maintain blood pressure homeostasis; high pressure leads to vasodilation and decreased heart rate, while low pressure causes vasoconstriction and increased heart rate.

Hormonal Blood Pressure Control

Involves hormones such as ADH, aldosterone, angiotensin II, renin, atrial natriuretic peptide (ANP), and epinephrine/norepinephrine, which regulate blood volume and vessel diameter.

Direct Renal Mechanism

Kidney mechanism that alters blood volume independently of hormones by influencing filtration and water reabsorption rates to regulate blood pressure.

Indirect Renal Mechanism (Renin-Angiotensin-Aldosterone System - RAAS)

Kidney mechanism where renin is released in response to low blood pressure, leading to the production of angiotensin II, which increases vasoconstriction and stimulates aldosterone and ADH release to raise blood pressure.

Major Arteries and Veins Identification

Refers to the process of recognizing and naming key blood vessels throughout the body, as typically illustrated in anatomical diagrams.