Bio 150- Cardiovascular System Flashcards
(49 cards)
Blood vessels:
arteries, arterioles, capillaries, venules, veins
Basic circuits:
Pulmonary, Systemic, Coronary, Hepatic Portal System
Components of the Cardiovascular System
- Heart=Pump blood around the body!
- Arteries & Arterioles=Carry blood AWAY from the heart (oxygenated or deoxygenated blood)
- Capillaries=Smallest blood vessels (very thin walled – why?) Connect arterioles and venules
- Venules & Veins=Carry blood back to the heart (deoxygenated or oxygenated blood)
- Blood!=Delivers nutrients and picks up wastes to/from the body’s tissues
Overall functions of the CVS
- Transport=Of gases (O2 and CO2), nutrients, waste products, processed molecules (eg., lactic acid), regulatory molecules (eg., hormones)
- Protection=Against foreign substances such as toxins or microorganisms (blood as part of the immune system)
- Maintenance/ Regulation =Of body temperature, normal pH, and osmotic composition (to maintain normal fluid and ion balance), plus restricting blood loss
Where is your heart?
-In the thoracic cavity, between the lungs, posterior to sternum
-Part of the mediastinum
Together with the trachea, esophagus, etc
(see Fig. 20-2b)
-Base: Deep to sternum + 2nd intercostal space
-Apex: Deep to the 5th intercostal space (~7-9cm to the left of the sternum)
Pericardium
A double-layered sac that surrounds the heart
Pericardial sac:
- Fibrous. Anchors heart to diaphragm, sternum, and in mediastinum
- Parietal pericardium has:
- Outer fibrous layer: Dense irregular CT
- Inner serous layer: Simple squamous epithelium plus areolar CT (thin)
Visceral pericardium
=epicardium
-Covering surface of heart
Cavity between parietal + visceral pericardium: filled with
pericardial fluid
Wall of the heart
- Epicardium (=visceral pericardium!) : Mesothelium + areolar CT
- Myocardium: thick middle layer. Cardiac muscle! *Arrangement of fibers
- Endocardium: inner layer. Thin. Simple squamous epithelium (“endothelium”) plus areolar CT
Superficial Anatomy of the Heart
-4 chambers of the heart are visible: Right and left ventricles Right and left atria (note the auricle of each!) -Grooves/ depressions: Coronary sulcus Anterior interventricular sulcus Posterior interventricular sulcus -Fat, blood vessels…
Right atrium:
Receives blood from superior and inferior venae cavae, and from the coronary sinus
Left atrium:
Receives blood from the pulmonary veins (4)
Right and left atria are separated by the
interatrial septum
Ventricles
Very thick, muscular walls!!
Blood flow:
atrium to ventricle
Right ventricle:
blood flows out via pulmonary trunk
Left ventricle:
blood flows out via aorta
R+L ventricles are separated by the
interventricular septum
Heart Valves
-Prevent backflow of blood through the heart
“Flaps” formed by folds in endocardium
-Atrioventricular valves: between atrium and ventricle
Right = tricuspid
Left = bicuspid (mitral)
-AV valves are connected to chordae tendinae (which are connected to papillary muscles of the ventricle walls).
Semilunar valves:
- in the aorta and pulmonary trunk
- Each has 3 pocket-like semilunar cusps
Blood flow through the heart
Blood from body (systemic circulation) to superior & inferior venae cavae then to right atrium then to right ventricle to pulmonary trunk to pulmonary arteries to lungs (pulmonary circulation) to pulmonary veins to left atrium to left ventricle to aorta (to coronary and systemic circulation)
Internal conduction system of the heart
- Modified cardiac muscle – conducts electrical signals through the heart
- Sinoatrial (SA) node (the pacemaker)
- Atrioventricular (AV) node (a delay occurs here…)
- AV bundle
- Bundle branches (L&R)
- Purkinje fibers: Penetrate and stimulate the myocardium
Innervation of the heart
- Innervated by the ANS: Sympathtic and Parasympathetic
- Both divisions are controlled by cardiac centers in the medulla oblongata