Histology Flashcards
what 2 systems makes up the circulatory system?
1) cardiovascular system
2) lymphatic vascular system
is the cardiovascular system closed or open?
a CLOSED system.
what does the cardiovascular system consist of?
- heart
- arteries
- capillaries
- veins
what are the 5 roles of the cardiovascular system?
1) transports O2 & nutrients to tissues
2) transports CO2 & metabolic waste from issue
3) temperature regulation
4) distribution of hormones & immune cells
5) reproductive function in males; penile erection
Where is the majority of the blood found?
in peripheral veins
describe the cumulative volume of the capillaries compared to the cumulative surface area of capillaries?
Cumulative volume = small
Cumulative surface area = huge
3 layer that make up blood vessels and where they are from inner to outer..
1) tunica intima = insipide
2) tunica media = middle
3) tunic adventitia =outer
what is the inner layer, tunica intimacy made up of?
- squamous epithelial cells = endothelial cells
- supported by a basal lamina & thin layer of connective tissue
what is the tunica media made up of?
smooth muscle
what is the outer layer, the tunica adventitia made up of?
supporting connective tissue
how is the tunica intimacy separated from the tunica media?
= internal elastic membrane (layer of elastic tissue)
how is the tunica media is separated from the tunica adventia?
= external elastic membrane (layer of elastic tissue)
what colour do elastic fibres stain?
stain black
where are the largest arteries found and what are they called?
Found
- closest to heart, aorta
Called
elastic arteries
why are the largest arteries called elastic arteries?
as they have many sheets of elastic fibres in their tunica media to prove elastic recoil
in large vessels, which part of the wall can obtain nutrients from the lumen and why ?
= only the inner part of the wall
- as they have their own vascular supply
what is the inner part of the vessels wall own vascular supply Called?
vasa vasorum
how many layers of smooth muscle do arterioles have?
what do arterioles lack?
= 1 or 2 layers of smooth muscle in their tunica media
= NO adventitia
when are arterioles important?
in controlling blood flow in a tissue
what are capillaries composed of?
what do capillaries lack in terms of their layers?
endothelial cells & a basal lamina
Lack;
- adventitia & media
what else do capillaries often have?
pericytes at intervals just outside the basal lamina
what are pericytes?
connective tissue cells that have contractile properties
what are the 3 types of capillaries?
1) continuous
2) fenestrated
3) sinusoidal or discontinuous
where are continuous capillaries found?
- muscle
- connective tissue
- lung
- skinn
- nerve
where are fenestrated capillaries found?
- mucosa of gut
- endocrine glands
- glomeruli of kidney
what do sinusoidal or discontinuous capillaries lack and what does this therefore allow?
lack a basal lamina
= allowing macromolecules & cells to pass through
where are sinusoidal or discontinuous capillaries found?
- liver
- spleen
- bone marrow
what are microvascular networks?
small arterioles connecting to a post-capillary venue through a network made up of meta-arterioles, through channels & capillaries
what are metarterioles?
smallest vessel before capillaries
what are venues?
smallest vessel after capillaries - stage between capillaries & veins
what do post-capillary venues lined with?
what do post-capillary venues contain?
- endothelial cell-lined
- containing a thin layer of connective tissue & pericytes
when vessels begin to acquire intermittent smooth muscle, what are cells in the tunica media layer called?
venues
what are veins composed of?
- tunica intima
- relatively thin but continuous tunica media consisting of a few layers of smooth muscle
how is the tunica media different in a vein compared to a muscle artery?
= thinner than would be found in a muscle artery
what are 2 examples of the largest vein?
1) vena cava
2) hepatic total vein
Yes or No.
Does veins have a thick tunica adventita?
yes.
Yes or No.
Are veins flexible… explain?
Yes - allows expansion & thus can contain most of the blood in the body
what are valves made of?
= inward extensions of the tunica intima
what is he main difference between an artery and a vein?
tunica media is thinner in a vein compared to an artery
what are the 3 layers of the heart and describe their location from inner to outside?
1) endocardium - inner
2) myocardium - middle
3) epicardium - outer
what structures does the endocardium contain? (5)
- endothelium
- basal lamina
- thin layer of collagen fibres
- layer of denser connective tissue
- sub-endocardium of loose connective tissue that contains small blood vessels & neves & branches of impulse conducting the system
what structures does the myocardium contain? (3)
- bundles & layers of contractile cardiac muscles fibres
- muscle fibres surrounded by connective tissue with rich network of capillaries (as its aerobic tissue)
where is the single nucleus located in cardiac muscle cells?
centrally
why do cardiac muscle cells have intercalated discs?
present to bolt cardiac muscle cells to their neighbour
what is mesothelium?
a single layer of flattened epithelium on surface of the heart
what does the epicardium contain?
- basal lamina
- fibro-elastic connective tissue & adipose tissue
where would coronary vessels be embedded?
in adipose tissue on surface of the heart
what are the 2 parts of the pericardium?
1) fibrous
2) serous (parietal & visceral)
what is the fibrous pericardium made up of?
sac of tough fibre-collagenous connective tissue
what is serous pericardium made up of?
layer of simple squamous epithelium (mesothelium) backed up by basal lamina & connective tissue
what are the two layers separated by?
a thin pericardial cavity which contains pericardial fluid for lubrication of the heart
what is the heart skeleton and what does it do?
= thick bands of fibrous connective tissue around the heart valves, between atria & ventricles.
- supports valves, providing attachment for cardiac muscle fibres
- electrically isolates the aria from he ventricles
what are heart valves made of?
- dense core of connective tissue = lamina fibres
- outer endothelial layer with a basal lamina
what are the leaflets of valves, separating the atrium from the ventricles, anchored to?
anchored to papillary muscles in walls of ventricle by collagenous strands celled chord tendinaea
what does the chord tendinaea merge with?
lamina fibrosa
Yes or No.
are there blood vessels in he valves?
no
where is the lamina fibres located?
core of the heart
what is the lamina fibrosa made up of?
dense irregular connective tissue that is continuous with fibrous skeleton of heart
what are the 3 types of cardiac muscle cells?
1) contractile cells
2) pacemaker cells
3) conducing cells
what are pacemaker cells?
specialised muscle cells
describe the size of pacemaker cells?
considerably smaller than contractile cardiac myocytes
histologically, how do they appear?
pale
describe the size of Purkinje Fibres?
larger than cardiac muscle cells
where are purkinje fibres found?
in sub-endocardial layer just deep to the endocardium
what does the lymphatic vascular system do?
consists of lymphatic vessels that drain tissue fluid, eventually returning it to veins in base of neck
describe the walls of the lymph system?
thin walls the drain excess interstitial fluid into blood stream
where does most of the interstitial fluid return?
capillaries & venous vessels
- but a portion returns to the circulator system
Yes or NO.
do lymphatic vessels have a central pump?
No.
- they have smooth muscle in walls, hydrostatic pressure in the tissue & compression of vessels by voluntary muscle, combined with valves in vessel which produces flow
