Blood vessels Flashcards
Define Arteries:
Conduct blood from heart to body organs.
Define Arterioles:
Medium calibre arteries branching into smaller ones.
Define Capillaries:
Small calibre vessels connecting arteries with veins at the tissue level.
Define Venules:
Several capillaries come together into small and medium venules.
Define Veins:
Larger vessels that conduct blood from body organs to the heart.
State the different functional classification of blood vessels: (5)
- conduction
- distribution
- Resistance
- Interchange
- Volume and return
What`s Conduction?
Larger vessels that conduct blood from body organs to the heart.
What`s distribution? (3)
- Medium calibre arteries.
- Smooth muscle tissue predominates in their wall.
- Regulation of regional distribution of blood flow.
What’s resistance regarding functional classification? (4)
- Smaller arteries or arterioles.
- Smooth muscle tissue predominates in their wall.
- Regulation of local circulation.
- Peripheral resistance depends on them.
Whats`s Interchange?
- Capillaries
* Exchange of substances between tissues and blood.
What’s volume and return?
- Veins
* Return blood to the heart.
When do we speak about Macrocirculation? What diameter and which vessels are included?
Vessels with a diameter >0.1 mm
- Large arterioles
- Muscular and elastic arteries
- Muscular veins
When do we speak about Microcirculation and what Vessels are included?
- Arterioles
- Capillaries
- Postcapillary venules
State the different layers of a blood vessel: (important)
- tunica interna (intima)
- tunica media
- tunica externa or adventitia
What does the tunica internal (intima) contain? What Histology features? (important)
- inner lining of vessels
- Composed of:
- Endothelium (weich) (squamous epithelium) faces the lumen
- Basement membrane: collagen fibres (zum Schutz, zum kräftigen)
- Subendothelium (um mit dem Rest zu connected) (connective tissue, few muscle fibres).
Function of internal elastic lamina, where present and what fibres are present? (4)
(important)
➢ Separates tunica intima and media.
➢ With fibres of elastin (single or few layer). Perforated (for the diffusion of molecules).
➢ Present in arteries and arterioles.
What layer is responsible for vasoconstriction and dilation?
Tunica Media
What does the tunica media contain? (important)
➢ It is the most variable of all layers.
➢ Composed of:
• Smooth muscle fibres circularly arranged (ANS control)
• Connective tissue in variable proportion: elastic, reticular
fibres, proteoglycans, and glycoproteins.
Which layer is the most variable?
Tunica media
What contains the external elastic lamina? (3)
➢ Separates tunica media and adventitia.
➢ With fibres of elastin (variable number of rows)
➢ Present only in muscular and elastic arteries.
What layer separates tunica media and adventitia?
External elastic lamina
Which vessel present the external elastic lamina?
only in muscular and elastic arteries
What tissue does the tunica external contain?
dense irregular connective tissue, longitudinally orientaded
What does the tunica externa compose? (4)
Composed of: • Collagen fibres (type I). • Elastic fibres. • Nerves (nervi vascularis). • Vasa vasorum (vessels supplying blood to vessel walls)
What fibers have fibroelastic connective tissue?
- collagen fibres (type I)
- elastic fibres
What’s a vasa vasorum?
Vessels supplying blood to vessel walls
What’s the function of arteries?
Conduction of blood from heart to organs
What diameter do arteries have?
diameter of 4mm
What makes the arteries special?
They contain a great amount of elastic fibres
How is it called when a vessel contains a great amount of elastic fibres?
Distensibility
What makes large arteries special?
They are really elastic
What makes medium arteries special?
They contain well organised muscular fibres
What arteries are really elastic?
- Aorta
- Common carotid
What do large arteries contain?
- Tunica externa or adventitia with vessels and nerve terminals
- Tunica media
- non organized muscle fibres with high amount of elastin fibres
- Well developed internal elastic lamina
- Tunica interna (intima)
- Thick sub endothelial layer
What’s a well developed layer of the aorta and common carotid artery?
internal elastic lamina
What do medium arteries contain?
Tunica externa or adventitia.
External elastic lamina. Variable amount of elastin.
Tunica media. Layers of well-organized muscular fibres.
Internal elastic lamina.
Tunica interna (intima) Thick subendothelial layer.
Whats the layer of the medium artery thats has a well organised muscles fibres?
Tunica media
What does the tunica interna of the medium arteries have?
Thick sub endothelial layer
Whats the function of small arteries?
Distribution
What kind of small arteries do we have?
- small calibre
- arterioles
Which one is bigger, small calibre or arterioles?
small calibre are 0.1-2mm
Does small calibre or arterioles contain more muscle fibres?
Small calibre: 8-10 layers of muscle fibres. No external elastic lamina.
What does the small calibre has that the arterioles dont have?
Internal elastic lamina
Whats the main characteristic of the arterioles? What makes it special?
Has a scarce in the tunica external
(areolar connective tissue and sympathetic nerves=
Which arteries count to big arteries?
- aorta
- common carotid
Which muscular artery medium sized do we have?
- femoral
- mesenteric
What are capillaries and what are their function?
Join arterioles and venules
Very narrow: allow exchange of substances with interstitial fluid.
Whats Microcirculation?
Microcirculation: blood flows from arteriole into capillaries into venules
What cells do capillaries have?
Pericytes (cells located in some areas of capillaries): contain actin and myosin. Formation of new vessels.
Whats the main function of capillaries?
Only 1 layer of endothelial cells + basement membrane
Which types of capillaries do we have?
- Continuous or Somatic
- Fenestrated or Visceral
- Discontinuous or Sinusoidal
Where can we find continuous or Somatic capillaries?
Muscle, connective tissue, lungs, nervous tissue
What membrane do continuous capillaries have?
Continuous endothelium and basement membrane.
Where can we find fenestrated capillaries?
(peritubular capillaries kidney, endocrine glands, intestine)
What membrane can we find in fenestrated capillaries?
Continuous basement membrane
Whats the characteristic of fenestrated capillaries?
Fenestrations (pores) + diaphragm
Whats the main characteristic of glomerular capillaries?
Large pores without diaphragm (pedicels)
Where can we find glomerular capillaries?
In the glomerulus of the kidney
What membrane do glomerular capillaries have?
Continuous basement membrane
What basement membrane do discontinuous capillaries have?
Incomplete or absent basement membrane
Where can we find discontinuous capillaries?
Liver, red bone marrow
Whats the main characteristic of discontinuous capillaries?
Wide, large fenestrations, intercellular cleft
Whats the function of sphincter? (relaxed)
control the flow of blood through the cap
Whats the function of the capillary bed?
a network of 10–100 capillaries that arises from a single metarteriole.
What are THOROUGHFARE channels?
metarterioles can serve as thoroughfare channels to the venules, bypassing the
capillary bed.
Where is the optimum condition for exchange found?
within capillaries
What is a anastomose?
• The union of the branches of two or more arteries supplying the same body region.
• They provide alternative routes for blood into an organ or a tissue, known as
Collateral circulation.
How are arteries called that dont have anastomoses?
End arteries
Whats the most developed layer in veins?
Tunica externa
Whats the layer that contain the most collagen and elastic fibers of the veins?
Tunica externa
Whats the layer that may be absent in veins?
The sub endothelial layer in the tunica media
Whats the function of veins?
transport blood from tissues to the heart.
What do veins NOT contain?
They present thin walls relative to their diameter (0.5 mm to 3 cm). No elastic laminas.
What is the main characteristic of veins?
The have valves
In what layer can we find the valves?
tunica interna
Whats the function of veins?
They project towards the heart,
preventing backflow of blood.
Histology of valves:
An endothelium over connective tissue with elastic fibres.
Can we find valves in all veins?
Only present in large veins
Where are valves more abundant?
More abundant in lower limbs.
Where can we find the lowest pressure regarding arteries and veins?
in vena cava
What can we say that venous system is?
Venous system is a blood reservoir
Where can we find the highest blood distribution?
in systemic vessels, arteries and arterioles 13%
Where can we find the mayor circulation?
in systemic circulation
Where can we find the minor circulation?
In pulmonary
How many coronary arteries do we have?
2, one right and one left
Which one do we count to the right coronary artery?
- marginal branch
- posterior inter ventricular branch
Which one do we count to the left coronary artery?
- Circumflex branch
- Anterior Interventricular branch
How many branches do we have in the aorta?
Three branches
State the 3 branches of the arch of the aorta:
- Brachiocephalic trunk with:
Right common carotid and right subclavian (with right vertebral) - Left common carotid
- Left subclavian artery with left vertebral
What goes from the brachicephali branch?
Right common carotid and right subclavian (with right vertebral
What can we find towards the right arm?
Brachiocephalic trunk: Right Subclavian artery, Axillary, Brachial, Radial, and Ulnar
What can we find towards the left arm?
Left Subclavian artery, Axillary, Brachial, Radial, and Ulnar
How many branches of the descending thoracic aorta do we have?
two:
- visceral branches
- parietal branches
Which ones contain the visceral branches?
- Pericardial
- Esophageal - Bronchial
- Mediastinal
Which ones contain the parietal branches?
Intercostals
Where do the visceral branches go to?
the internal organs
Where do the parietal branches go to?
To the body walls
Which structures can we find below the diaphragm?
- celiac trunk
- superior mesteric
- renal
- inferior mesenteric
Which arteries do the celiac trunk contain?
Left gastric
- Common hepatic - Splenic
Which arteries do the superior mesenteric contain?
- Small intestine
- Right colic (colon)
Which arteries do the renal contain?
none
Which arteries do the inferior mesenteric contain?
- Left Colic
- Superior recta
Which arteries do the celiac trunk contain?
Left gastric
- Common hepatic - Splenic
Which arteries do the superior mesenteric contain?
Small intestine
- Right colic (colon)
Common iliac artery:
- internal iliac
- external iliac
Which arteries do the external iliac contain?
Femoral artery
- Popliteal artery
- Tibial artery
- Fibular artery
Oxygenated blood returns to:
FOUR pulmonary veins
Systemic (deoxygenated) blood returning to:
- Coronary sinus
- Superior vena Cava
- Inferior Vena Cava
Function of superior vena cava:
Collects blood from upper limbs, head, and thorax
Right brachiocephalic
- Right Subclavian from External Jugular
- Internal Jugular
- Right Vertebral
Left brachiocephalic
Left Subclavian from External Jugular
Internal Jugular
Left Vertebral
SUPERIOR VENA CAVA function:
Collects blood from upper limbs, head, and thorax
Azygos System
− Esophageal Veins
− Bronchial Veins
− Intercostal Veins
Inferior vena cava function:
Collects blood from lower limbs and abdominal cavity
Inferior Vena Cava contains:
− Hepatic − Splenic − Mesenteric − Renal − Testicular/Ovaric
