Cardiovascular System (Heart (myocardium - microscopic (fasciae adherens: …
myocardium - microscopic
- region where intercalated discs connect
Also contains: T-tubules, myofibrils, sarcoplasmic reticulum, and mitochondria.
- second heartbeat
- blood flow from ventricle to pulmonary trunk or aorta.
- first heartbeat
- blood flow from atrium to ventricle
Layers of heart wall:
- Epicardium: visceral pericardium
- Myocardium: spiral-shaped muscle to aid in ringing out blood
- Endocardium: lines heart and covers valves
SA (sinoatrial) node:
- electrical signals contract right atrium
AV (atrioventricular) node:
- triggered by SA node
- send message to AV bundle
- Bundle of HIS
- passes electrical impulses down AV septum and up sides (purkinje fibers)
- contracts heart forcing blood upwards
- keeps heart in place
- prevent overfilling of heart
- contains serous fluid
- lubrication and free movement
- Simple Squamous epi & aerolar CT
- Visceral: touches muscle
- Parietal: outer layer
- most abundant
- least "leaky" only sm. material can pass
- found in smooth and skeletal muscle, lungs, skin, etc.
- has pores
- easy quick exchange of material
- sm. intestine, kidney, etc.
- lg. pores, holes
- large, high exchange of material; ex. whole cells
- liver, bone marrow, etc.
- more tunica ext.
- less tunica med.
- contains valves; blood travel against gravity
- less elastic fibers
- smallest veins
- 1-2 layers of smooth muscle
- most muscle
- send blood to organs
- can dilate and constrict
- largest, closest to heart
- moves lg. amounts of blood
- moves blood through stretch and recoil
Arterioles (little arteries):
- 1-2 layers of muscle
- will change diameter
- contains iron
- binds and transports O2
- shape increases surface area for O2 absorption.
- sm. parts of larger cells - megakaryocyte.
- helps with blood clotting.
- 90% water
- 10% composed of 100+ molecules (sugar, lipids, hormones, etc.)
- Albumin: keep water in vessels
- Globulin: act as antibodies and transporters
- Fibrinogen: helps with blood clotting