Cardiorespiratory Flashcards
List the heart valves
Valves
- Tricuspid valve
- Bicuspid (mitral) valve
- Pulmonary valve
- Aortic valve
How is the heart innervated?
- Parasympathetic stimulation decreases heart rate (Vagus nerve)
- Sympathetic stimulation from sympathetic trunk increases heart rate
- Together form cardiac plexus
What are the three layers of the heart wall?
- Epicardium (visceral pericardium)
- Myocardium- thickest layer, cardiac muscle
- Endocardium- innermost, lines the chambers
Describe the appearance of microstructure of cardiac muscle
•Striated appearance
Intercalated discs
- Fascia adherens
- Desmosomes
- Gap junctions
- Normally 1 nucleus per cell
- Branching pattern
- Do not divide
What are the anatomical features of the lungs (Lobes)
Left
- 2 lobes
- oblique fissure
- Impression for the heart (the cardiac notch)
- Lingula
Right
- 3 lobes
- horizontal fissure and oblique fissures
describe the respiratory tree
- Trachea
- Main bronchi
- Secondary (lobar) bronchi (3 x right, 2 x left)
- Tertiary (segmental) bronchi
- Bronchioles
- Alveoli
Features of smooth muscle
Functions
- Not striated
- Spindle shaped
- One central nucleus
- Involuntary control- nervous, hormonal or electrical depolarization
- Found in walls of tubular structures and hollow viscera
Functions:
- Regulates diameter
- Propels liquids and solids
- Expels contents
What is the endothelium?
What is the function of the endothelium?
•Monolayer of squamous epithelial cells
Functions:
- Control vascular tone and vessel diameter
- Regulate permeability
- Angiogenesis
- Regulate clotting
- Regulate immune response
Clinical conditions associated with blood vessels
- Thrombosis:
- Blood clot (thrombus)
- Stray blood clot (embolism)
- Atherosclerosis
- Angiogenesis as a target for cancer treatment
What are the layers of a blood vessel wall?
Tunica intima
- Lined by endothelium
- Basement membrane (basal lamina)
- Connective tissue
Internal elastic lamina
Tunica media
- Primarily smooth muscle
- Connective tissue- elastic and collagen fibres
External elastic lamina
Tunica externa (adventitia)
- Outer connective tissue layer- primarily collagenous
- Can contain nerves and vessels (vasa vasorum)
What is the immediate distribution of arteries coming out of the left ventricle of the heart?
Aorta (aortic arch)
Brachiocephalic trunk
Left common carotid
Left Subclavian artery
Features of large elastic arteries
- Large diameter (>10mm)
- Tunica media contains many layers of elastin
- Windkessel effect
- Supplied by vasa vasorum
Vascularity in the left arm
Left subclavian artery
|
Left axillary artery
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Left brachial artery
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Left radial artery ^ Left ulnar artery
Medium muscular arteries features
- Smaller diameter (0.1mm-10mm)
- Thick layer of smooth muscle in tunica media
- Vasoconstriction and vasodilation
- Pulsatile contractions
- Most named arteries
Small arteries and arterioles (resistance) features
- Narrow lumina
- Decreased thickness of all layers
- Tunica media predominantly smooth muscle, 1-2 cell layers in thickness
•Tonus dictates degree of filling of capillary beds
- Not normally named during dissection
- Arterioles microscopic - ≤0.3 mm
- No external elastic lamina
Features of capillaries
- Endothelial layer with basement membrane (basal lamina)
- Allow exchange between blood and extracellular fluid
- Microscopic (5-10µm)
- No tunica media or tunica externa
What are the three types of capillary?
Where are they found?
- Continuous- uninterrupted endothelium, complete basement membrane (most common)
- Fenestrated- pores (fenestrae), complete basement membrane (endocrine glands, the intestines, pancreas and kidney)
- Sinusoidal (discontinuous)- large pores, incomplete basement membrane (liver, red bone marrow, spleen)
How do capillaries facilitate exchange of fluid?
- Hydrostatic pressure forces fluid out of blood into extracellular fluid
- Exchange occurs between extracellular fluid and tissue cells
- Osmotic pressure drives fluid is reabsorption
Features of venules
- Microscopic (8-100µm)
- Progressively increase lumen diameter
- No elastin
- Very thin tunica externa and media
- Internal and external elastic lamina absent
Vascular drainage of the left arm
Median Cubital vein
Left brachial - left basilic - left cephalic veins
Left axillary vein
Left subclavian vein
Features of veins
- Under lower pressure -> tunica media thinner
- Larger diameter than arteries
- Smaller veins are TRIBUTARIES of larger veins
- More variable
•Large veins have well developed tunica adventitia/ externa and thin tunica media
•Internal and elastic membrane absent
Venous supply to the superior vena cava
internal jugular + Subclavian vein + axillary –> Brachiocephalics vein –> Superior vena cava
Venous valves
- Inward projection of intima, strengthened by collagen and elastic fibres
- Semi lunar cusps attached to the venous wall
- Absent in thorax and abdomen
- Dilation of veins can mean valves don’t close, resulting in varicose veins
Describe the relationship between arteries and veins
Large arteries
Smaller arteries
Superficial veins
Large arteries with single vein e.g. aorta, axillary, femoral
Smaller arteries flanked by 2 veins (venae comitantes) enclosed in a sheath
- Pulsation of the artery aids venous return -> arteriovenous pump
- Countercurrent mechanism to heat regulation
Superficial veins do not have corresponding arteries
