M8S2 Blood Vessels

Question 1

Structure of blood vessels

Answer 1

Outer->inner

Tunica externa
-aka adventitia
-outside layer
-composed of connective tissue with collagen and elastic fibres

Tunica media
-middle layer
-composed of smooth muscle and elastic fibres

Tunica intima
-inner layer
-composed of simple squamous epithelium, aka endothelium
*refer to goodnotes image

Question 2

Blood vessel overview

Answer 2

-2 different types of blood vessels in cardiovascular system: arteries and veins
(Listing in big to small for each category)
Arterial System:
1. Elastic artery
-largest arteries near the heart, such as aorta
-aorta one of the major blood vessels branching off of the heart
Main characteristics: large lumen, tunica media has more elastic fibers than smooth muscle, exhibit stretching and recoil characteristics
2. Muscular artery
-deliver blood to various regions and organs of body
Main characteristics: thick tunica media with a lot of smooth muscle, exhibit contractile characteristics
3. Arteriole
-muscular arteries typically lead to large arterioles, which then lead to small arterioles
-large arterioles have three tunics but the tunica media consists of only a few layers of smooth msucle
-small arterioles have a single layer of smooth muscle around the tunica intima

Venous system
1. Veins
-small and large
Main characteristics: larger lumen compared to arteries, far less muscle in tunica media compared to arteries, veins have one-way valves that prevent blood flowing backwards
2. Venule
-smallest venues resemble capillaries in structure, as consist of only one tunic
-small ventless give rise to larger venues that have 3 tunics, each being extremely thin
-much larger lumen and diameter compared to capillaries and arterioles

Capillaries
-smallest blood vessels and transition between arterioles and venues
Main characteristics: diameter ranging from 8-10 muemeters, consists of only the tunica intima (layer of endothelial cells plus a thin basement membrane)
*refer to goodnotes

Question 3

What forms when blood vessels don’t work properly

Answer 3

Spider or varicose veins