Ch. 22 + 23: Heart And Blood Vessels Flashcards
Arteries
- carry blood away from the heart
Veins
Carry blood back to the heart
Great vessels
- arteries and veins entering and leaving the heart
What do heart valves do
Make sure that blood flow is unidirectional
Pulmonary circulation
- right side of the heart pumps deoxygenated blood to the pulmonary arteries
- pulmonary veins carry blood to the left side of the heart
Systemic circulation
- left side of the heart pumps oxygenated blood through systemic arteries to the bodies cells
- exchanges nutrients, gasses, and wastes are exchanged and carried through systemic veins
Mediastinum
- space located slightly left of the midline, deep to the sternum
Where is the right boarder locatated
More anteriorly
Pericardium
- tough sac
- restricts heart movements so that it moves only slightly within the thorax
Fibrous pericardium
Tough outer sac
Serous pericardium
- composed of parietal and visceral layers
Pericardial cavity
- thin space between layers of serous pericardium containing serous fluid
Function of fibrous pericardium
- made up of dense irregular connective tissue
- prevents overstretching of the heart
- provides protection
- anchors the heart in the mediastinum
Serous pericardium consists of
- parietal pericardium
- visceral pericardium
- pericardial fluid
Epicardium
- most superficial layer
a visceral layer of the serous pericardium and areolar connective tissue
Myocardium
- middle layer
- cardiac muscle
- thickest of the three layers
Endocardium
- most deep layer
- internal surface of the heart chambers
- simple squamous epithelium and Ariel or connective tissue
Intercalated discs are made up of:
Desmosomes
Jap junctions
Sulci
Marks the boundary between two heart chambers
Coronary sulcus
Marks the boundary between superior atria and inferior ventricles
Anterior interventricular sulcus
Marks the boundary between the left and right ventricles
Posterior interventricular sulcus
Marks the boundary between the ventricles on the posterior side of the heart
Right atrium receives blood from
- vena cava
- coronary sinus
Coronary sinus
Deoxygenated blood from the heart surface
Pectinate muscles
Are internal smooth ridges on the atrial wall
What is between the right atria and ventricle
Tricuspid valve
Trabeculae carnae
Raised bundles of smooth muscular ridges
Papillary muscle
Cone shaped muscular projections
Chordae tendineae
Strands of collagen fibers
Septomarginal trabecula
- secures papillary muscles to the interventricular septum
Left atrium receives blood from the
Pulmonary veins
What valve is between the left atria and ventricle
Bicuspid / mitral
Left ventricle
The thickest - pumps blood to the rest of the body
Conus arteries is
Smooth wall conical region
Atria characteristics
- thinner
- generate less blood pressure to deliver blood a short distance
Ventricle characteristics
- three times thicker
- generate more pressure
Fibrous skeleton functions
- prevent overstretching of the valves
- secure valves if the heart wall
- point of intersection for bundles of cardiac muscle fibres
- provides electrical insulation between atria and ventricles
Four dense connective tissue rings
- pulmonary fibrous ring
- aortic fibrous ring
- right atrioventricular fibrous ring
- left atrioventricular fibrous ring
Av valves
Tricuspid
Bicuspid (mitral)
Semilunar valves
- allow ejection of blood from the ventricles
- prevent the back flow of blood into the heart
Right marginal artery
- supplies the right boarder of the heart
Posterior interventricular artery
- supplies posterior surface of the left and right ventricles
Anterior interventricular artery
- also called; “left anterior descending artery”
- supplies the anterior surface of both ventricles and most of the inter-ventricular septum
Circumflex artery
- supplies the left atrium and ventricle
Great cardiac vein
- runs alongside the anterior interventricular artery
Middle cardiac vein
- runs alongside the posterior interventricular artery
Small cardiac vein
Travels close to the right marginal artery
Nervous system and cardiac
- certain hormones can alter the pace of contractions, but the nervous system does not initiate contractions
Autorhythmicity cells
Initiates it’s own heartbeat
Conducting system
Specialized cells that start and propagate electrical impulses to contractile cells
Arteries
Carry blood away from the heart to other organs
Capillaries
- are at a cellular level; are exchange vessels
Veins
Venues merge to form larger blood vessels called veins
Tunica interna contains
- endothelium
- subendothelial layer
- internal elastic lamina
Endothelium
- innermost lining, simple squamous epithelium
Subendothelial layer
- made up of areolar connective tissue
- provides physical support base for the epithelial layer
- collagen fibres provide tensile strength, stretching, and recoiling
Internal elastic lamina
- separates T. Intima from T. Media
Tunica Media
- muscular and connective tissue layer
- relatively thick; composed of smooth muscle cells and large amounts of elastic fibres
- smooth muscles: adjust the diameter of the lumen wall to regulate blood flow and blood pressure
Sympathetic nervous system
Innervates smooth muscles of blood vessels
External, elastic lamina
- separates T. Media from T. Externa
Tunica Externa
- forms covering and consists of elastic and collagen fibres
- numerous nerves
- tiny blood vessels that supply tissue of the vessel wall: called vasa vasorum or vessels to the vessels
- seen on large vessels such as the aorta
- T. Externa anchors the vessels to the surrounding tissue
Luman diameter
A: narrower
V: wider
General wall thickness
A: thicker
V: thinner
Cross sectional shape
A: retains circular shape
V: flatten (collapse) if no blood is in veins
Thickest tunic
A: tunica media
V: tunica Externa
Elastic and collagen fibres in tunics
A: more
V: less
Valves
A: none
V: present in most
Blood pressure
A: higher
V: lower
Blood flow
A: away from heart
V: towards heart
Blood oxygen levels
A:
- systemic: high in oxygen
- pulmonary: low in oxygen
V:
- systemic: low in oxygen
- pulmonary: high in oxygen
Three types of arteries
- elastic
- muscular
- arterioles
Elastic / conducting arteries
- largest
- most located near the heart
- allow stretch
- branch into muscular arteries
Examples of elastic arteries
- aorta and pulmonary trunk
- brachiocephalic
- subclavian
- common carotid
- common iliac arteries
Muscular / distribution arteries
- medium sized
- more smooth muscles and fewer elastic fibres
- well defined internal elastic lamina
- no ability to recoil and help propel blood through them
Contains T. Media - has vascular tone
Examples of muscular arteries
- brachial
- anterior tibial
- coronary
- inferior mesenteric
Arterioles / resistance vessels
- smallest arteries
- generally al, have less than six cell layers of smooth muscle in tunica media
Sympathetic interaction to muscle fibres of tunica media causes vasoconstriction - elevates blood pressure (upstream) and decreases local blood flow (downstream)
Exchange vessels
Capillaries
- smallest blood vessels
- consist solely of tunica intima: single layer of endothelial cells and basement membrane
- allow metabolic exchange between blood and tissues
Continuous capillaries
- the plural membranes of endothelial cells form a continuous tube, except interrupted only by intercellular clefts
Continuous capillaries location
- muscles
- the brain
Fee started capillaries
- plural membranes of endothelial cells have many fenestrations
Fenestrated capillaries location
- small intestine
- kidney
Sinusoids
- wider and more winding
- have large fenestrations
- contains incomplete or absent basement membrane
- lager intercellular clefts
Intercellular clefts
- allow proteins and in some cases even blood cells to pass from a tissue into the bloodstream
Sinusoids location
- bone marrow
- liver
Venules
- smallest veins
-companion vessels with arterioles - merge to form veins
Smallest venules
Post capillary venules
Diapedesis
Leukocytes migrating from the bloodstream to intestinal fluid
- occurs through walls of post a pillar venules
Fetal blood circulation occurs through
The placenta
How do fetuses obtain oxygen nutrients and eliminate Corbin dioxide and wastes
Through maternal blood
Ductus arteriosus postnatal structure
- ligamentum arteriosum
Ductus venous postnatal structure
Ligamentum venous
Foremen ovale postnatal structure
Fossa ovalis
Umbilical arteries postnatal structure
Medial umbilical ligaments
Umbilical vein
Round ligament of the liver (ligamentum teres)