Bio 150- Cardiovascular System Flashcards
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
Circulation In general:
Leave the heart… Arteries Arterioles Capillaries Venules Veins …back to the heart!
3 main layers (tunics) of a typical blood vessel:
- Tunica interna (intima): Endothelium, BM, and maybe an internal elastic membrane
- Tunica media: Smooth muscle (!) plus collagen, plus maybe an external elastic membrane
- Tunica externa (adventitia): CT
Blood vessels >1mm in diameter need their own blood supply=
vasa vasorum
Arteries and arterioles:Structure and function
- Carry blood AWAY from the heart
- Elastic arteries: biggest. Can withstand high pressures. Lots of elastic tissue, less smooth muscle
- Muscular arteries: medium-small. Lots of smooth muscle. Adapted for vasoconstriction and vasodilation.
- Arterioles: smallest arteries with the 3 tunics (?)… Carry blood to capillaries. Capable of vasoconstriction and vasodilation
Capillaries:Structure and function
- Endothelium and BM
- Very small (RBCs can just barely fit through… often need to fold!)
- Thin walled – allow for diffusion!
Veins and venules:Structure and function
- Carry blood back to the heart
- Venules: similar to capillaries, but larger diameter
- Medium and large veins: tunica adventitia is the predominant layer
- Have valves! :Prevent back flow of blood, Folds of the tunica intima, Present in veins >2mm in diameter, More valves in the veins of the lower body than the upper body
Blood supply TO the heart! (coronary circulation)
- The muscle of the heart needs a blood supply, too!
- Right & left coronary arteries branch off of the aorta. Lie in the coronary sulcus.
- Cardiac veins return blood to a cavity called the coronary sinus, then blood flows back into the right atrium
Pulmonary circulation
- Blood flow from heartlungs to heart
- To allow for gas exchange in the lungs!
- Deoxygenated blood leaves right ventricle, goes to lungs (via pulmonary arteries), gets rid of CO2 and picks up O2
- Blood returns to the heart via pulmonary veins to left atrium
Systemic circulation
- Blood flow from heart to body to heart
- Oxygenated blood leaves the left ventricle to aorta to body
- Comes back to the heart via the venae cavae to right atrium
Blood supply to the brain
- Blood flows up through the external and internal carotid arteries, plus the vertebral arteries in the neck
- Interesting feature: the arterial circle (aka “circle of Willis”)
Portal Systems
- Portal systems carry blood from one capillary bed to another capillary bed (before returning to the heart)
- 2 in the body: Hypophyseal portal system and Hepatic portal system -Hepatic portal system carries blood from the “gut” to the liver
Blood tissue
-A type of connective tissue! (remember?)
-Makes up ~7% of your body weight! (~5L)
-Non-cellular components:
Plasma (blood’s ECM)
~46-63% of blood
Composed of water, proteins, and other solutes
-Formed elements:
~37-54% of blood
Blood cells
Blood: non-cellular components
Plasma: water (92%) plus proteins and other solutes (a colloid)
plasma proteins:
- Albumins: helps to maintain blood osmotic pressure, and carry some substances
- Globulins: transport molecules and antibodies
- Fibrinogen: important in formation of blood clots
Blood: cellular components (formed elements)
-Erythrocytes: Red blood cells ~99.9% of formed elements of blood Transport O2 and CO2 -Leukocytes: White blood cells Several different types… each with specific functions (such as phagocytosis, promoting and reducing inflammation, producing antibodies…) -Platelets (thrombocytes): Blood clotting
Blood: erythrocytes
-Biconcave discs
-No nucleus in mature erythrocytes!
Life span of ~120days
-Contain the protein hemoglobin:
Gives blood its red colour
Carries O2 (and some CO2), and can also carry CO
Blood: types of leukocytes
-Granulocytes: Large granules inside each cell, pick up specific stains Lobed nuclei (3 types, named for how they stain) -Agranulocytes: No granules visible with light microscopy Nuclei not lobed (2 types)
Blood: granulocytes
Neutrophils
Eosinophils
Basophils
Neutrophils
Granules pick up acidic and basic stain Most common WBC Nuclei: 3-5 lobes Phagocytic Can leave the bloodstream
Eosinophils
Granules pick up only the acidic stain (eosin)
Nuclei: usually bi-lobed
Reduce inflammation (can enter inflamed tissues. Common in allergic response.)
Basophils
Granules pick up only the basic stain
Nuclei: 2 lobes
Release histamine and heparin (functions of each?), can also leave bloodstream
Blood: agranulocytes
Lymphocytes
Monocytes
Lymphocytes
Smallest of the WBCs Nucleus fills most of the cell Many different types Most are in lymphatic tissues Produce antibodies, plus other roles in immune response
Monocytes
Largest WBCs (usually)
Nucleus: round, or “blobby”…
Phagocytic (can leave the bloodstream)
Can engulf and break down foreign particles, then signal the immune system
Blood: thrombocytes
-Cell fragments (platelets)
-Can stick together and to other tissues…
-Involved in blood clotting:
Form platelet plugs
Release chemicals necessary for forming a blood clot
