Next week Quiz on vascular anatomy – Bold terms and background information Biopac ECG This week Cardiac muscle- distinguish between cardiac, skeletal, and smooth Vascular anatomy

5-2 Three types of Cell Junctions 1.Tight – fusion of plasma membrane; Seals off intercellular space; prevents substances passing between cells 2. Gap (communicating) junction— connected by a connexon - six transmembrane proteins (orange segment arrangement) surrounding water-filled pores - Rapid transport of ions, glucose, amino acids, and other solutes pass from one cell to the next (heart) 3. Desmosomes- Hooklike J-shaped proteins arise from cytoskeleton patch that holds cells together; keep cells from pulling apart (resists mechanical stress)

Cardiac muscle Figure Desmosomes – mechanical linkage Gap junction - ion flow

Cardiac Muscle

Skeletal muscle

Smooth muscle

Vascular anatomy Ch. 20

20-14 Introduction The route taken by the blood after it leaves the heart was a point of much confusion for many centuries – Chinese emperor Huang Ti (2697–2597 BC) believed that blood flowed in a complete circuit around the body and back to the heart – Roman physician Galen (129–c. 199) thought blood flowed back and forth like air; the liver created blood out of nutrients and organs consumed it – English physician William Harvey (1578–1657) did experimentation on circulation in snakes; birth of experimental physiology – After microscope was invented, blood and capillaries were discovered by van Leeuwenhoek and Malpighi

Function of vessels Arteries carry blood _____ ____ the heart. Capillaries allow _______ of blood (fluids) with tissues. Veins carry blood _____ the heart.

Vascular Anatomy Capillaries Simplest Thin tube (one cell wide-8µm) of endothelial cells Transport of substances from blood to interstitial fluid – Driven by balance of hydrostatic pressure and osmotic potential Two types of transport – Continuous- endothelial cells are fused by tight junctions Transport diffusion through cell membrane and vesicular transport – Fenestrated- pores through cells allow rapid exchange chorid plexus of brain, liver, reproductive system

They both have – Tunica interna-endothelial cells and basal membrane and supporting tissues – Tunica media-middle layer of smooth muscle (does not show on model) – Tunica externa- outer layer of connective tissue Tunica media is bigger in arteries than veins to withstand pressure from heart contractions (pulse) Veins have valves to prevent back flow of blood (less pressure) Vascular Anatomy Arteries and Veins

Fig. 20.2

Tunica interna has more foldings in artery Fig. 20.1

Fig

Superior mesenteric artery

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