Ch 21 Cardiovascular System Flashcards
1
Q
Functions of the circulatory system
A
- Carry blood
- Exchange nutrients, waste products and gases
- Transports substances - such as hormones, components of the immune system, molecules requires for coagulation, enzymes, nutrients, gases and waste products
- Regulate blood pressure
- Directs blood flow
2
Q
What are the structural features of blood vessels?
A
Arteries
- elastic
- muscular
- arterioles
Capillaries
- site of exchange with tissues
Veins
- thinners walls than arteries, contain less elastic tissue and fewer smooth muscle cells
- venules
- small veins
- med or lrg veins
3
Q
Capillaries
A
- walls consist of epithelial cells
- substances move through capillaries by diffusion through:
- lipid soluble and small water soluble molecules through plasma membrane
- large water soluble molecules pass through gaps between endothelial cells
4
Q
Types of capillaries
A
- Continuous
- No gaps between endothelial cells
- No fenestrae
- Less permeable to large molecules than other capillary types. Eh muscle, nervous tissue
- Fenestrated
- Have pores
- Endothelial cells have numerous fenestrae
- Fenestrae are areas where cytoplasm is absent and plasma membrane is made of a thin, porous diaphragm
- Highly permeable
- Sinusoidal
- Large diabetes with large fenestrae
- Less basement membrane eg. Endocrine gland
- Sinusoids
- Large diabetes Sinusoidal capillaries
- Sparse basement membrane eg. Liver, bone membrane
- Venous sinuses
- are similar in structure but even larger eg. Spleen
5
Q
arteries and veins
A
- Tunica Intima
- endothelium
- basement membrane
- internal elastic membrane
- Tunica Media
- smooth muscle cells arranged circulatory around the blood vessel
- vasoconstriction: smooth muscles contract, decrease blood flow
- vasodilation: smooth muscles relax, increase blood flow
- Tunica Externa
- connective tissue
- varies from dense regular near the vessel to loose that merges with the surrounding CT
