Cardiovascular System

Advanced Biology Spring 2013 Cardiovascular System Vocabulary Development Angio- vesselAther- porridge Brady- slowDiastol- dilation Edem- swellingGram- something writtenLun- moonMyo- musclePapill- nipple Phleb- veinScler- hardSyn- togetherSystol- contractionTachy- rapid IntroductionCardiovascular system- all blood vessels, capillaries, veins, arteries, & heart make up the cardiovascular system Blood vessels form 2 circuits:Pulmonary circuit- sends oxygen poor blood to the lungs to pick up oxygen & unload carbon dioxideSystemic circuit- sends oxygen rich blood & nutrients to all body cells & removes wastes

Structure of the Heart Size & Location of the Heart Size varies with body size (average adult: 14 cm long & 9 cm wide) Inside the thorax Rests on the diaphragm

Structure of the Heart Coverings of the Heart Pericardium- encloses the heart & the proximal ends of the large vessels that are attached to it Fibrous pericardium- outer fibrous layer that protects the double layered serous membrane Parietal pericardium- inner lining of the fibrous pericardium Visceral pericardium- inner most layer of the double membrane & directly covers the heart muscle Pericardial cavity- space between the parietal & visceral pericardia filled with fluid

Structure of the Heart Wall of the Heart 3 distinct layers: Epicardium- outer layerProtects the heart by reducing frictionSerous membrane consists of connective tissue Includes capillaries & nerve fibers Myocardium- middle layer Thick & consists mostly of cardiac muscle tissue that pumps blood out of the heart chambers Endocardium- inner layer Consists of epithelium & underlying tissueContains blood vessels & specialized cardiac muscle fibers called Purkinje fibers Lines all chambers of the heart & covers the structures that project into them

Structure of the Heart Heart Chambers & ValvesDivided into 4 hollow chambers; 2 left & 2 right Atria- upper chambers Thin wallsReceive blood returning to the heart Auricles- small projections of the atria that increase atrial volume slightlyRight & left atrias are separated by the interatrial septum Ventricles- lower chambersForce blood out of the heart into arteries Right & left ventricles are separated by the interventricular septum Ventricles & atria on each side of the heart are separated by atrioventricular orifice which is guarded by an AV valve (atrioventricular valve)

Structure of the Heart Heart Chambers & Valves Right atrium Receives blood from 2 large veins: superior vena cava & inferior vena cavaBoth return blood low in oxygen from tissues Coronary sinus- drains blood into the right atrium from the myocardium of the heart Right atrium is separated from the right ventricle by a tricuspid valve (right atrioventricular valve) Allows blood to flow from the right atrium into the right ventricle but not in the other direction

Structure of the Heart Heart Chambers & ValvesRight Ventricle Thinner muscular wall than the left ventricle Pumps blood short distance through the pulmonary trunk which divides into the left & right pulmonary arteries that lead to the lungs Pulmonary valve is at the base of the trunk (pulmonary semilunar valve) & prevents blood from flowing back in the right ventricle from the pulmonary trunk

Structure of the Heart Heart Chambers & Valves Left atrium Receives blood from 4 pulmonary veins (2 from each lung) Blood passes from the left atrium to the left ventricle through the atrioventricular orifice through a mitral valve (bicuspid valve; left atrioventricular valve)Prevents blood from flowing back into the left atrium from the left ventricle

Structure of the Heart Heart Chambers & Valves Left Ventricle Contracts & sends blood through the aorta which branches out and sends blood to all parts of the body Aortic valve (aortic semilunar valve; tricuspid) opens to allow blood to leave the left ventricle but not to go back into the left ventricle Mitral & tricuspid valves are also called atrioventricular valves because they are between the atria and ventricles Pulmonary & aortic valves are called semilunar valves because of the half-moon shaped cusps

Path of Blood Through the Heart Blood from systemic circuits Venae cavae & coronary sinusRight atriumThrough tricuspid valve Right ventricle Through pulmonary valve Pulmonary trunkPulmonary arteries Alveolar capillaries (lungs) Pulmonary veinsLeft atriumThrough mitral valveLeft ventricleAortic valveBlood to the systemic circuit 12Blood Supply to the Heart Cardiac Veins Coronary sinus Right atrium Heart Actions Actions are regulated so thatAtria contract, atrial systole, while the ventricles relax, ventricular diastoleVentricles contract, ventricular systole, while the atria relax, atrial diastole Both atria & ventricles relax for a brief moment These actions make up a complete heartbeat and is called the cardiac cycle Heart chambers function in a coordinated fashion. Their actions are regulated so that the atria contract, called artrial systole, while the ventricles14Heart Actions Cardiac Cycle Changes in pressure in the heart chambers during a cardiac cycle cause valves to open & close During ventricular diastole (atrial systole) the pressure difference between atria & ventricles opens the AV valves allowing the ventricles to fillDuring ventricular systole (atrial diastole) the AV valves are closed, atria are relaxed and blood flows back into the atria as the ventricles contractBlood Vessels Form a closed circuit of tubes that carries blood from the heart to the body cells and back Includes: ArteriesArteriolesCapillariesVenulesVeins Blood Vessels Arteries & arterioles conduct blood away from the ventricles of the heart & lead to capillaries Arteries- carry blood at high pressureArterioles- arteries sub divide into progressively thinner tubes & give rise to arterioles Capillaries- smallest-diameter blood vessels, connect the smallest arterioles & venules Venules & veins return blood from the capillaries to the atriaVenules- microscopic vessels that come from capillaries and merge to form veins Veins- carry blood back to the atria & follow pathways similar to the arteries

Paths of Circulation Pulmonary circuit- consists of vessels that carry blood from the heart to the lungs and back to the heart Systemic circuit- carries blood from the heart to all other parts of the body and back again & include coronary circulation Paths of CirculationPulmonary CircuitPulmonary trunk of right ventricle Pulmonary trunk is divided into the left & right pulmonary arteries, which enter the right & left lungs Lobar Branches 3 in right2 in left Lobar branches divide into arterioles Arterioles divide into networks of capillaries Alveolar capillaries exchange gases between the blood & air Taking out carbon dioxide and putting in oxygen Paths of Circulation Pulmonary Circuit contPulmonary venules Alveolar capillaries send oxygen rich blood herePulmonary venules join to form smalls veinsSmall veins join to form the 4 pulmonary veins return blood to the left atrium2 from each lung

Paths of CirculationSystemic CircuitFreshly oxygenated blood moves from the left atrium to the left ventricle Left ventricle contracts pushing blood into the aorta, which branches out and sends oxygenated blood to all of the body tissues Left ventricle contraction is also responsible for the force that returns blood to the right atrium to start the pulmonary circuit Arterial System AortaLargest diameter artery in the body Extends upward from the left ventricle & arches over the heart to the left & descends just in front of and to the left of the vertebral column several branches

Arterial System Principal Branches of the Aorta Ascending aorta- part of the aorta that sends blood up; first part of the aortaAortic sinus- swelling in the aortic wall, behind each cusp of the aortic valveRight & left coronary arteries begin here Includes the arch of the aorta Arterial System Arch of the Aorta 3 major branches of the ascending aorta Brachiocephalic- supplies blood to the tissues of the upper limb & head Divides into:Right common carotid artery- carries blood to the right side of the neck and head Right subclavian artery- carries blood to the right arm Left Common Carotid- carries blood to the left side of the neck Left Subclavian Artery- carries blood to the left arm Arterial System Descending Aorta Directly in front of the vertebral column Thoracic aorta- part of the descending aorta above the diaphragm Branches include:Bronchial artery- supplies blood to the bronchi Pericardial artery- supplies blood to the pericardium Esophogeal artery- supplies blood to the esophagus Mediastinal artery- supplies blood to the mediastinum (area above the diaphragm surrounding the heart and lungs) Posterior intercostal artery- supplies blood to the thoracic wall Abdominal aorta- part of the descending aorta that is below the diaphragm Divides into several different arteries

Arterial System Branches of the Abdominal Aorta Celiac artery- supplies organs of the upper digestive tract Splits into gastric, splenic, and hepatic arteries Phrenic artery- supplies the diaphragm Superior mesenteric artery - supplies portions of the small & large intestines Suprarenal artery- supplies the adrenal glands Renal artery- supplies the kidneyGonadal artery- supplies the ovaries or testes Inferior mesenteric artery- supplies the lower portion of the large intestineLumbar arteries- supply the posterior abdominal wall Middle sacral artery- supplies the sacrum & coccyx Common iliac artery- supplies the lower abdominal wall, pelvic organs, and lower limb Arterial System Arteries to the Brain, Head, & Neck Branches of the subclavian & common carotid arteries supply blood to the structures of the head, brain, and neck Vertebral arteries come from the subclavian arteriesBasilar artery- runs along the ventral brainstem & branches out leading to the pons, midbrain, & cerebellum Posterior cerebral arteries- supplies parts of the occipital & temporal lobes of the cerebrum Thyrocervical arteries- branches and supplies blood to thyroid gland, parathyroid glands, larynx, trachea, esophogus, & pharynx Costcocervical arteries- supply blood to muscles in the neck, back, & thoracic wall Arterial System Arteries of the Head, Neck, & Brain contCommon carotid arteries divide to form internal & external carotid articlesExternal Carotid ArteryUpward on the side of the head & branches out to structures in the neck, face, jaw, scalp, & base of the skull Main vessels of the external carotid artery Superior thyroid artery- hyoid bone, larynx, thyroid glandLingual artery- tongue, muscles of the tongue, salivary glands beneath the tongueFacial artery- pharynx, palate, chin, lips, noseOccipital artery- scalp on the back of the skull, the meninges, mastoid process, muscles of the neckPosterior auricular artery- ear & scalp over the ear Terminates by dividing into maxillary & superficial temporal arteries

Arterial System Arteries of the Head, Neck, & Brain contInternal Carotid Artery Provides the major blood supply to the brainMajor branches: Ophthalmic artery- supplies the eyeball & muscles & accessory organs associated with the orbit Posterior communicating artery- forms part of the cerebral arterial circle Anterior choroid artery- supplies the choroid plexus within the lateral ventricle of the brain & to nerve structures of the brainTerminates by dividing into the anterior & middle cerebral arteries Arterial System Arteries to the Shoulder & Upper LimbSubclavian artery passes through the first rib and clavicle and turns into the axillary artery Axillary artery- supplies branches to structures in the axilla & chest wall, part of the mammary gland, the upper end of the humerus, the shoulder joint, muscles in the back, shoulder, & chest Turns into the brachial artery when it leaves the axilla Brachial artery- along the humerus to the elbow; supplies the triceps and other muscles in the upper arm Branches at the elbow into the radial & ulnar arteries30Arterial System Arteries of the Shoulder & Upper Limb contUlnar artery- travels down the ulnar side of the forearm to the wrist; supply blood to the flexor and extensor muscles in the forearmRadial artery- continuation of the brachial artery, travels down the radial side of the forearm to the wrist; supplies the lateral muscles of the forearm Arterial System Arteries of the Thoracic & Abdominal Walls Branches from the subclavian artery and the thoracic aorta feed the thoracic & abdominal walls Internal thoracic artery- originates in the base of the neck and passes downward behind the upper six ribs Branches in to 2 anterior costal arteries at each rib Anterior costal arteries- supply the intercostal muscles Posterior intercostal arteries- branch from the thoracic aorta & supply the intercostal muscles, the vertebrae, the spinal cord, & deep muscles of the back

Arterial System Arteries of the Pelvis & Lower Limb Common iliac arteries- branch from the abdominal aorta at the pelvic brim & supply blood to the pelvic organs, gluteal regions, & lower limbs Descend & divide into internal & external branches Internal iliac artery branches include: Iliolumbar artery- supplies the ilium & muscles of the back Superior & inferior gluteal arteries- supplies the gluteal muscles, pelvic muscles, & skin of the buttocks Internal pudendal artery- supplies the alimentary canal, the external genitalia, & the hip joint Superior & inferior vesicular arteries- supplies the urinary bladder & in males also the supply the seminal vesicles & prostate gland Middle rectal artery- supplies the rectumUterine artery- supplies the uterus & vaginaArterial System Arteries of the Pelvis & Lower Limb cont External iliac artery- provides the main blood supply to the lower limb 2 large branches: inferior epigastric artery & deep circumflex iliac artery Supply the muscles & skin in the lower abdominal wall Femoral artery- has many branches Superficial circumflex iliac artery- supplies lymph nodes & skin of the groin Superficial epigastric artery- supplies the skin of the lower abdominal wall Deep femoral artery- supplies the hip joint & muscles of the thigh; largest branch of the femoral artery Deep genicular artery- supplies the distal ends of thigh muscles & the anastomosis around the knee joint

Arterial System Arteries of the Pelvis & Lower Limb Popliteal artery- supply blood to the knee joint & to certain muscles in the thigh & calf Femoral artery becomes the popliteal artery Anterior tibial artery- runs between the tibia & fibula & supplies the skin & muscles in the anterior & lateral regions of the leg Posterior tibial artery- beneath the calf muscle & supplies the skin, muscles, & other tissues of the lower legMedial & lateral plantar arteries-supply the instep, heel, & toes Fibular artery- extends downward along the fibula