Cardiovascular System Flashcards
Cardiovascular System
- Circulatory System
- Capillaries
- Structure of large vessels
- Structure of Arteries
- Structure of Veins
- The heart
- Lymphatic
Vascular Systems
- Circulatory System
- Lymphoid System
- *Oxygen content of arteries and veins is REVERSED in systemic and pulmonary systems.
(PIC)
Capillaries
Capillaries and postcapillary venules are the exchange vessels for the tissues
Structure of Capillaries
- Endothelial Cells
- Basal Lamina
- Pericytes (help maintain viability of endothelial cells)
Types of Capillaries: Continous Capillary Found in
Muscle, Skin, lung, brain
Types of Capillaries: Fenestrated Capillary Found in
Intestines, Endocrine, kidneys (fenestrated sinusoids with wider diameter)
Types of Capillaries: Sinusoidal (discontinuous) Capillary Found in
Liver, Spleen, Bone Marrow, Endocrine
Capillary Exchange Mechanisms
- Open pores/gap
- diffusion
- filtration
- Vesicular transport (Transcytosis)
- Transendothelial Channels
Vascular Transport
-System of pinocytotic pits and vesicles which move large molecules across the endothelium
Transendothelial Channels
Vesicles are so numerous sometimes that they form a channel in which fuild/larger molecules transport more rapidly
Secretory and Metabolic Functions of Endothelial Cells
- Adhesion molecules (diapedesis-process when eosinophils can squeeze)
- Produce vasoactive compounds Anti-thrombogenic factors
- Metabolic conversions (angiotensin I to II)-vasoconstriction
Structure of Arteries and Veins
Tunica Intima, Tunica Media, Tunica Adventitia
Tunica Intima
Endothelium, connective tissue, Internal Elastic Lamina (IEL)
Tunica Media
Smooth Muscle, elastic fibers, EEL (thicker in arteries, thinner in veins)
Tunnica Adventitia
Connective tissue +vv+ nerves (thinner in arteries, thicker in veins)
Artery VS. Vein
Artery has larger Tunnica Media (PIC)
Characteristics of Venules and Arterioles
LOOOK AT CHARRRTTTT
Aorta: (Elastin Stain)
Elastin first appeared phylogenetically with the evolution of closed high pressure circulatory systems (jawed fish). Unique to gnathostome vertebrates
- Need elasticity of aorta to pump blood through the body
- Elastin fibers are reliant to blood vessels expanding and contraction
Muscular (distributing) Arteries
- Elastic Lamina NOT in veins
- Elastic Lamina usually is not folded but fully plump from blood being full and stretching it
Arteriole have how many layers of smooth muscle?
<5
Types of Microcirculation
- Arteriole-Capillary Bed-venule (MOST COMMON)
- Arteriovenous anastomosis (skin) (SHORT CIRCUIT CIRCULATION)
- Arteriole-capillary-arteriole (kidney)
- Venule-Capillary-venule (liver), Hepatic portal system
Blood pressue varies through vessels starting in ____ to the ____
Arteriole, Venus System
Structure of the Vein
-not all veins have tunica media
-tunica dventisia is thickest
-in cross sections, tunica adventicia budles have a directionality (perpindicular to those of tunica media
-veins have valves bc of low blood pressure
-valves prevent form flowing backwards
PICS
Medium Sized Vein
- Large lumen
- no scalloped relastic lamina
- adventitia
Large Sized Vein
Vena Cava has smooth muscle
- Thin tunnica media
- Tunnica Adventitia has bundles of smooth muscle
purpose of valves in veins
facilitate blood flow in unidirectional blood flow
Structure of Heart
Built on a cardiac skeleton of high density collagen connective tissue
Endocardium- homologous to tunica intima
Myocardium- homologous to tunica media
Epicardium-homologous to tunica adventitia
Functions of Purkinje Fibers
a specialized cardiac muscle cell that conducts impulses 5x faster than surrounding cells. Gap junctions allow the wave of depolarization to first induce cardiac muscle contractions from the apex of the heart
EpiCardium components
fat/adipose cells
Endocardium
where purkinji fibers are found
Function of Lymphatic Vessels and Lymph Nodes
- Return Excess 10% of interstitial fluid to blood
- Trasnport lipids absorbed from intestines
- Immunologic support
Lymphatics
Lymphatic Capillaries have unique remeability charactersitics, filaments (elastic fibers) anchor to connective tissue
How do we recognize the lymphatic vessel from the vein?
Recognize bc lymphatic vessel contains lymphocytes
- no RBC
- Cells with Nuclei
Veins hasve no lymphocytes and RBC
Lymphatic Vessels and Lymph Nodes
All lymph get filtered by at least one lymph node before it re-enters the blood
-Lymph node pathology used for prognosis of metastases