term 4 week 1 anatomy of heart etc Flashcards
(31 cards)
3 layers (inside → out)
* Endocardium
* Myocardium
* Contractile tissue
* Pericardium
* Visceral (epicardium)
* Parietal
* 4 chambers
* 4 valves
The Heart
- Pulmonary
- Systemic
- Lymphatic vascular system
Circulatory System
The internal surface of all components of these systems is lined with a single layer of squamous epithelium called the …..
Endothelium
* Selectively permeable
* Antithrombogenic
endocardium
- Endothelium
- Middle myoelastic layer of smooth muscle and connective tissue
- Subendochondral layer that merges with the myocardium
the thickest heart layer
Myocardium
Double-walled sac
* Outer parietal pericardium
* Inner visceral pericardium (epicardium)
Pericardium
skeletal muscle characteristics
fiber type - single multinucleated cells
striations - present
nuclei location - peripheral
SR - well developed
special structures - well organized sarcomere, SR, T tubule system
control of contraction - Troponin C binds Ca 2+ , moving tropomyosin and exposing actin for myosin binding
Key function - voluntary movements
efferent innervations - motor
contractions - all or none triggered at motor end plates
cell response to increased load - hypertrophy
capacity for regeneration - limited involving satellite cells
cardiac muscle characteristics
fiber type - branched arrangement, one nucleus
striations - present
nuclei location - central
SR - less developed than skeletal
special structures - intercalated discs with many gap junctions, numerous mitochondria
Key function - automatic pumping of blood
efferent innervations - autonomic
contractions - all or none, intrinsic (beginning at nodes of conducting cells)
cell response to increased load - hypertrophy same as skeletal
capacity for regeneration - very poor
Intercalated discs
- Interface between adjacent
cardiac muscle cells
- Gap junctions
- Provides ionic continuity between cells
- Serves as electrical synapses
- Allows cells to act like a multinucleated syncytium
Myocardium – 2 cell types
Mechanical Cells
Conductive Cells
Receives deoxygenated blood:
* SVC
* IVC
* Coronary sinus
* Normal pressure 0-8mmHg
* Central venous pressure
Right Atrium
Ejects blood into the pulmonary
circulation
* Pulmonary arteries
* Pressures are low
* 0-8mmHg diastole
* 15-30mmHg systole
Right Ventricle
Thicker wall than R atrium to
adapt to high pressure of blood
returning from lungs
* Via _________________
* Normal filling pressure 4-
12mmHg
pulmonary veins
and this is all about the
Left Atrium
Myocardium is 3x thicker than R
ventricle
* Normal pressures:
* 80-120mmHg (systole)
* 4-12mmHg (diastole)
Left Ventricle
Valves
2 atrioventricular valves
* Tricuspid (right)
* Bicuspid (left)
* Prevent backflow of blood from
the ventricles into the atria during
systole
* Cusps are attached to papillary
muscles of the myocardium by the
chordae tendinae
2 semilunar valves
* Lie between the ventricles and the
arteries
* Prevent backflow of blood from
the arteries during diastole
All vessels of the circulatory system
except capillaries contain _____ _____ in addition to the endothelial
lining
smooth muscle
- Non-thrombogenic surface on which blood will not clot
- Actively secretes agents that control clot formation
-Heparin, tissue plasminogen activator (tPA), von Willebrand factor - Regulates vascular tone and blood flow
-Secretes agents that stimulate smooth muscle contraction - Endothelin I, angiotensin-converting enzyme
- Secretes agents that stimulate smooth muscle relaxation
- Nitric oxide
- Prostacyclin
Endothelium
Layers of the blood vessel
- Tunica intima – innermost layer
- Endothelium and subendothelial layer of loose connective tissue
- Tunica media – middle layer
- Concentric layers of helically arranged smooth muscle
- Tunica externa (adventitia) – type I collagen and elastic fibers
- Large vessels also have vasa vasorum
- “vessels of the vessel”
- Help provide metabolites to cells in large vessels that cannot be provided by
perfusion
Vasa vasorum
meaning “vessels of vessels” in Latin, are small blood vessels that supply the outer layers of larger arteries and veins
Elastic Arteries
- Aorta, pulmonary artery, and their
large branches - Conducting arteries
- Contains large amounts of _____
- Vessels under the most pressure
elastin
Elastic Arteries
Carotid sinuses – slight dilations of the bilateral internal carotid arteries, aortic
arch
* Act as baroreceptors monitoring arterial BP
* Contain sensory nerve endings from cranial nerve IX
* Brain will process afferent impulses and adjust vasoconstriciton to maintain BP
Chemoreceptors – found in carotid bodies and aortic bodies
* Monitor CO 2 and O 2 levels
* Release neurotransmitters
Secondary structures
Distribute blood to the organs
* Help regulate BP by contracting or
relaxing smooth muscle in the
media
* Contains a large amount of smooth
muscle cells
* 40 layers
Muscular Arteries
Arterioles
Muscular arteries branch repeatedly into smaller and smaller arteries
* Reach a size with 1 or 2 smooth
muscle layers
* Indicate the beginning of the
microvasculature
* Less than 0.1mm in diameter
* Exchanges between the blood and
tissues occur
