Anatomy of Bloodflow Through Heart 1 Flashcards
describe the bloodflow through pulmonary and systemic and hepatic portal circulations
- right atrium receives deoxygenated blood from systemic circulation (cranial and caudal vena cava)
- directed to right ventricle (tricuspid valve)
- exits pulmonary trunk –> pulmonary arteries to lungs through the pulmonary valve
- left atrium to the left ventricle (mitral valve) and exit via aorta (aortic valve)
- arterial blood to the head, neck and forelimbs via subclavian and common carotid arteries
- arterial blood to body tissues via descending and abdominal aorta –> hepatic portal system in liver
- venous returns to right atrium via cranial and caudal vena cava
where is the heart within the thorax in left lateral view
between ribs 3-6 at an angle with its base lying cranial and dorsal to the apex which lies caudal and ventral
what is the position of heart in dorsoventral view
lies to the left of midline
apical heart beat
what is the cardiac notch
the region of the heart which is in direct contact with the body wall
the heart is sitting surrounded by mediastinal pleura –> passing over the lateral surfaces of the heart and holding it here between the left and right thorax
where is the heart relative to the mediastinum
within its own serious sac (pericardium) within the middle mediastinum
what are the structures of the middle mediastinum
what structure covers the heart
pericardium
tough structure –> fibrous material (not much flexibility, can cause problems if fluid build up or heart enlarges)
what are the structures of the pericardium
divided into visceral and parietal layers
vsiceral layer –> adherent to surface to heart and reflects over great vessels and then adheres to the fibrious layer that is between the mediastinum
pericardium is filled with fluid –> between parietal and visceral layer (continuous with outersurface of the heart –> epicardium) –> serous fluid fills this gap
what are the layers of the heart
- epicardium (outer)
- myocardium (middle)
- endocardium (inner)
what is the epicardium layer composed of
- superficial layer (visceral pericardium)
- deeper fibroelastic CT
what is the myocardium layer composed of
- cardiac muscle
- endomysium CT
what is the endocardium layer composed of
- endothelium and CT
- purkinje fibres
what type of epithelium is the endocardium
simple squamous epithelium
how is cardiac muscle arranged
in circular and spiral arrangement of cardiac muscle bundles in the myocardium
networks to ensure proper directional flow when they contract and squeeze the blood through the different chambers of the heart
identify the histological features of the cardiac muscle
list 5 histological features of the cardiac muscle
- striated muscle with centrally located nuclei
- branching myofibres
- purkinje fibres
- intercalated discs (connections between myofibres that allow for unified contraction of sarcomeres)
- endomysium (CT running between the myofibres)
what view of the heart is this and why
right lateral view
- between apex and base –> coronary groove (1/3 down), fat filled that forms a band around the heart
- right inter-ventricular groove is seen (separates the entire ventricular mass into two)
- cranial and caudal vena cava coming into the right atrium
identify the base and apex
identify the coronary groove
identify right inter-ventricular (subsinuosal) groove
identify major blood vessels entering the right atrium
- coronary groove –> usually fat filled and contains coronary blood vessle
- right inter-ventricular groove –> contains coronary blood vessels (defines position of right and left ventricles, cranial and caudal margins of the heart are defined)
- major blood vessels entering right atrium –> caudal vena cava, cranial vena cava and right azygous vein
identify the view of the heart and the structures
right lateral
- right atrium
- caudal vena cava
- aorta
- right azygous vein (opening into the cranial vena cava)
identify which view of the heart this is
left lateral view (auricular surface)
can you see 1 or more auricles (blind ending sacs associated with each atrium)
identify the coronary groove
identify the left inter-ventricular groove or paraconal groove
identify the ventricle that forms the apex
identify where the aorta arises from
- coronary groove (fat filled) –> interrupted on the left side by a large blood vessel (pulmonary trunk)
- left inter-ventricular groove or paraconal groove –> cranial margin = right ventricle, caudal margin = left ventricle
- left ventricle forms the apex
- aorta arises from middle of base, medial to pulmonary trunk and to the left of the esophagus
identify the view shown and the structures
left view of heart
- left auricle
- pulmonary trunk
- right ventricle
- left ventricle
- left azygous vein
what view of the heart is this
right view
what view of the heart is this
left
identify the structures and the view of the heart shown
right lateral
identify the view and the structures
left lateral view
what are the structures
- right atrium
1’. right auricle
- right ventricle
- right atrioventricular valve
- caudal vena cava
- intervenous tubercle
- cranial vena cava
- terminal crest
- fossa ovalis
how does venous return from systemic circulation enter the heart
blood entering right atrium from:
- cranial vena cava and caudal vena cava (intervenous tubercule separates flow)
- azygous vein –> venous return lumbar region (also l. azygous vein in ruminants and pigs)
- coronary sinus: venous return coronary circulation
what separates the flow of the cranial and caudal vena cava
intervenous tubercule
identify the structures
coronary sinus: sitting on top of atrial ventricular septum –> where venous return of coronary vessels
identify the structures of the right atrium and auricle (blood flow)
left arrow: caudal vena cava and coronary sinus
x: interveouns tubercule
top right: azygous vein and cranial vena cava
list the main anatomical features of the interior of the right atrium (5)
- thin walled, smooth lining
- auricle –> blind ending sac with pectinate muscles
- inter-atrial septum –> position of fossa ovalis –> remnant of fetal circulation –> foramen ovale
- terminal crest –> position of SA node; AV node at inter-ventricular septum
- right AV valve or tricuspid valve (3 cusps)
identify the structures of the interior of the right atrium
what is the impulse conducting system of the heart
AV bundle within interventricular septum directs the impul se to the apex –> trabecula septomarginalis –> impuse to papillary muscles in preparation for ventricular contraction
what are the structures
- vagosympathetic trunk
- sympathetic trunk
- middle cervical ganglion
- 4’. cranial and caudal limbs of ansa subclavia
- vertebral node
- cervicothoracic ganglion
- communicating branches
- 8’. caudodorsal and caudoventral cervicothoracic nodes
- vertebral cardiac nodes
- 10’. third and seventh thoracic ganglia
- thoracic cardiac nodes
- left recurrent laryngeal nodes
- 13’. cranial and caudal vagal cardiac nodes
what are the structures of the heart wall
endocardium: inner lining of heart, where blood is flowing over and will be continuous with blood vascular system want smooth and low friction –> simple squamous epithelium (endothelium)
serous pericardium: (visceral layer, epicardium) fatty material, fibrous CT and the visceral layer of the pericardium
