Anatomy 2- Exam 1

ANATOMY AND PHYSIOLOGY 2

CHAPTER 18

The endocrine system works with the nervous system and coordinates all the body systems.

The endocrine system uses hormones produce by endocrine structures.

-Effects are produced by these hormones

Hormones effect cells in their local environment or in distant parts of body.

Autocrine hormones- secreted by a cell and binds with that same cell

Paracrine hormones- local, secreted into the interstitial fluid of one cell and act on near body cells

Circulating hormones- hormones that travel and work over long distances (secreted into interstitial fluid, absorbed by blood stream, and carried systematically to any target cell that displays the appropriate type of receptor)

Lipid Soluble Hormones- bind with receptors in cytoplasm or nucleus of a cell

Steroid hormones- derived from cholesterol

Thyroid hormones- (T3 or T4) synthesized by attaching iodine to the amino acid tyrosine

Nitric oxide (NO) - can be both a hormone and a neurotransmitter

1) Bind with cell with receptors in cytoplasm or nucleus2) Activated receptor-hormone complex alters gene expression (turns genes on/off)3) Newly formed mRNA directs synthesis of specific proteins on ribosomes4) New proteins alter cell’s activity

Water Soluble Hormones- bind to receptors on the surface of a cell

Amine hormones- synthesized by modifying specific amino acids (melatonin/histamine)

Peptide hormones and protein hormones- amino acid polymers (longer chains of amino acids)

Eicosanoids-

Prostaglandins- important in playing a role in inflammatory response

Leukotrienes- important in playing a role in inflammatory response

Water Soluble hormones have to bind with a first messenger to get into the cell

1) Binding of hormone (first messenger) to its receptor activates G protein, which activates adenylate cyclase

2) cAMP serves as a second messenger to activate protein kinases

3) Activate protein kinases phosporlyate cellular proteins4) Millions of phosphorylated proteins cause reactions that produce physiological

responses

Prostaglandins (PGs) - hormones with local control

Important in mediation of pain, platelet aggregation, fever, inflammation

Important for smooth muscle contraction, gastric acid secretion, airway size.

Effects of Hormones

1) Hormones balance the volume and composition of body fluids2) Regulate metabolism and energy production3) Direct the rate of timing of growth and development4) Exerting physical and mental control during stress (physical trauma, starvation,

hemorrhage)5) Oversee reproductive mechanisms

Endocrine System Glands- secrete endocrine hormones into bloodstream

Exocrine- excrete products via ducts

Endocrine- when stimulated it will release hormone in frequent bursts (increases concentration of that particular hormone in the bloodstream)

Hormone secretion is regulated by impulses from nervous system, chemical changes in blood, and other hormones

Most hormonal regulatory systems work through negative feedback system

EX: (Parathyroid hormone (PTH) is important for controlling blood-calcium levels)

PTH exerts effects into body until calcium levels are leveled out

Positive feedback system- oxytocin stimulate contraction, which stimulate more oxytocin release

The endocrine systems consists of different glands throughout body (pituitary gland, thyroid glands, parathyroid glands, adrenal glands, pineal glands)

Other glands that are important in endocrine system but not endocrine function hypothalamus, thymus, pancreas, ovaries, testes

Endocrine contributions from other organs- kidneys, stomach, liver, small intestine, heart, skin.

The Hypothalamus- major link between nervous system and endocrine system

Receives inputs from many regions of brain (from thalamus/limbic system)

The Pituitary gland- the hypothalamus is mainly controlled by pituitary gland

Hangs down from hypothalamus on infundibulum

Divided into Posterior and Anterior pituitary (Anterior accounts for 75% of mass)

Posterior- (neurohypophysis)-

Anterior division (adenohypothesis) - anatomically and functionally connected to hypothalamus by blood vessels (form portal system- hypophyseal portal system)

Portal system- blood from capillary network into vein into another capillary network, then it returns to heart

Usually named to indicate the location of the second capillary network

Specialized cells in hypothalamus that secrete releasing hormones (secreted into portal system)

Tropic hormones- produced and secreted by the anterior pituitary- they target other endocrine glands (exception: hGH, Prolactin, MSH go directly to target organs)

Posterior pituitary- release, but not synthesize hormones

When stimulated neurosecretory cells in hypothalamus releases hormones like oxytocin and ADH

Oxytocin- involved in a positive feedback (birthing) – targets smooth muscle uterus/breast tissue- stimulates uterine contractions

ADH- target the collecting ducts in kidneys and sweat glands in skin. (Goal is to minimize water loss) Also causes arterials to constrict (by constricting, ADH helps increase blood pressure)

Pituitary Gland Disorders-

Acromegaly- excess hGH during adulthood) - enlargement and elongation of facial bones and hands

Diabetes Insipidus (DI)- (juvenile diabetes) caused by insufficient release of ADH from the neurohypophysis (without ADH acting on collecting duct in kidney, there is normal urine output of 1-1.5 liters a day to 2.5 liters a day- causes dehydration and loss of ions)

The Thyroid Gland-

Located inferior to larynx and anterior to trachea

There are 2 laterally placed lobes, connected by Isthmus

Spherical groups of follicular cells (thyroid follicles) store about a 100 day supply of the amount of hormone you need

Thyroid hormones-

TGB- large glycoprotein- made from oxidizing and adding iodine to molecules of amino acid (tyrosine) (hormones released- T4 and T3)

T4 and T3 are found in blood (most of T4 is released from thyroid then converted into T3)

Thyroid hormone accelerates growth (nervous and skeletal mostly)

TSH (thyroid stimulating hormone) - released from anterior pituitary gland

Goiter- enlargement of the thyroid gland (can be associated with hyperthyroidism and hypothyroidism)

The Parathyroid Glands-

Small round masses- attached to posterior surface of the left and right lobes of thyroid gland

Usually 2 attached to each lobe of thyroid gland

Calcitonin- secreted when blood calcium levels need to be lowered

Made by parafollicular cells of thyroid (C-cells)

Parathyroid hormone- is made from chief cells

Increases absorption of calcium (in GI tract)

Stimulation of osteoclasts so that calcium is released from bone into blood

Adrenal Glands-

There are 2 adrenal glands superior to each kidney (sometimes called suprarenal glands)

During embryonic development- the adrenal glands differentiate between 2 distinct/ functional regions

Adrenal Cortex- makes up 80-90% of the total weight of this gland

Subdivided into 3 separate zones that secrete a different group of steroid hormones

-Zona Glomerulosa secretes mineralocorticoids-mainly aldosterone

-Zona Fasciculata secretes glucocorticoids- mainly cortisol

-Zona reticularis secretes androgens- mainly masculinization hormones

Mineralocorticoids- function is to regulate concentration sodium and potassium in blood (affects blood volume and blood pressure) (aldosterone is one of the main hormones)

Glucocorticoids- function is to influence glucose metabolism (important to resist the effects of stress) (cortisol is one of the main hormones)

-Regulate metabolism by promoting breakdown of proteins and fats- when they are broken down they produce glucose (process is called glucogenesis- increase blood sugar levels and assist body with coping with stress) used in part of inflammatory response- because they inhibit white blood cells. They slow tissue repair and wound healing

-Glucocorticoids- used for chronic inflammatory disorders (can have long term side effects) Can be used for Lupus

-Addison’s Disease- autoimmune disorder (can become hypoglycemic easily/low sodium levels/low BP/dehydrated more easily/muscle weakness)

Androgens- masculinizing hormones (sex hormones) little effect on men, but important in the libido of women

RAAS: Renin-Angiotensin-Aldosterone System –important in increasing or decreasing blood pressure and blood volume as a response to stress (dehydration/hemorrhage) it is a 16 step process

Adrenal medulla- Deep to adrenal cortex (much smaller part of adrenal gland- about 20%)

Modified sympathetic ganglion- developed from same tissue as other sympathetic ganglion in other parts of nervous system

Secretes Epinephrine (80%) and Norepinephrine (20%)- help prolong the sympathetic response throughout body

There is a connective tissue capsule covering the outside of the adrenal gland

Pancreas

Endocrine gland and exocrine gland

Located posterior and inferior to stomach

Acini- clusters of exocrine cells-produce digestive enzymes and flow through ducts in GI tract

Pancreatic islets (islets of Langerhans) distribute along Acini (secrete 4 types of cells)

Alpha cells- secrete glucagon (important for increasing blood- glucose levels and converting glycogen into glucose)

Beta cells- secrete insulin

Delta Cells- secrete somatostatin

F cells- secretes pancreatic polypeptides

Insulin- decrease blood glucose levels- acts on hepatocytes (liver cells) converts glucose to glycogen- facilitates diffusion of glucose into cells

Somatostatin- act in a paracrine manner (local control of hormone) (inhibits both insulin and glucagon of Alpha and Beta cells) (inhibits secretion of HGH

Gonadal Hormones

Ovaries- produce several steroid hormones (2 types of estrogen/ progesterone)

Estrogen and LH and FSH control menstrual cycle

Estrogens- estradiol and estrone

Progesterone- relaxin and inhibin

Ovarian hormones- Female secondary sex characteristics- Progesterone

Testes- oval glands found in scrotum

Testosterone- androgen (male sex hormone) –important and needed for production of sperm/maintenance and development of secondary sex characteristics in males

Pineal Gland

Melatonin- secreted by pineal gland (important for maintaining internal biological clock- daily/seasonal cycles) more melatonin is secreted in darkness.

Thymus Gland

Thymosin- promotes proliferation and maturation of T cells (type of white blood cell-destroy microorganisms and foreign substances in body)

Lymphocyte-

General Adaptation Syndrome- (stress response)

Three stages-

Alarm reaction- short lived fight or flight response (initiated by hypothalamus- mediated by sympathetic division of ANS) (when we are in this reaction there are large amounts of oxygen and glucose in brain/lungs/skeletal muscles)

Resistance reaction- initiated by hypothalamic region- release hormones that are longer lasting- cortisol/thyroid hormones- tells our tissues to sustain metabolic)

Exhaustion- occurs when the body’s reserves become so depleted that it can no longer sustain the resistance reaction (large amounts of cortisol can cause muscles to waste) Suppression of the immune system happens as well/ ulceration in GI tract

1) What are functions of hormones (regulate chemistry composition/volume of internal environment/ regulate metabolism/ secretion of glands/ control growth and development)

2) Local hormones- paracrine/ Autocrine and circulating hormones3) Water-soluble/ lipid soluble hormones- steroids4) How to circulate hormones (signals from nervous system/ chemical changes in blood/

releasing of other hormones/ combination of above)5) The different Glands (pituitary -7 types of hormones-anterior/posterior/how

hypothalamus controls release of hormones/ Thyroid/Parathyroid gland- thyroid stimulating hormone (TSH) T3 and T4- feedback systems- how we get calcium in and out of blood and controlling high or low levels in blood/ Pancreas- islet cells (alpha and beta cells- glucagon) Feedback systems in pancreas (insulin/sugar)/ Rest of glands

6) General Adaptation System

CHAPTER 19

The Blood

Blood is important for contributing to homeostatic balance

-It transports repertory gases/ nutrients/ circulating hormones

It is body wide

Regulates body pH and temperature

Provides protection (plotting mechanisms/immune defenses)

About 5 Liters of blood in body (a little less than 1 and half gallons)

Blood is considered a connective tissue

Many different kind of cells that are suspended in salt water solution (plasma)

Little more viscous/dense than water

Blood is slightly warmer than body temperature

Blood is slightly more alkaline (more basic- 7.3-7.4 pH)

When blood sits out (it coagulates) (pinning in centrifuge separates quicker into:

Cellular portion-

Sediment-

55% blood plasma and 45% formed elements

Plasma- 92% water/ dissolved solutes other 8% (proteins/electrolytes/ gases)

Red blood cells (RBCs) - far more numerous than WBCs, interspersed together

Normal RBC mass/volume is called hematocrit (H-CT) (women-38-46/men 40-58)

The range is due to individual physiology/ physical fitness levels

They outnumber WBCs 700 to 1

Shaped- biconcave – important functionally because it increases surface area (more oxygen)

Because they don’t have mitochondria- they don’t use any of the oxygen they carry

They can form and fit into tight spaces

Mature RBC will not have a nucleus or other protein making machinery

Have a life span of about 120 days (much longer than platelets)

Since they don’t have a nucleus they are not really cells at that point (they really are the remnants of cells)

Purpose is to carry oxygen to all of body tissues

Reticulocytes- immature RBCs (low retic count (-.5%) indicates low rate of erythropoiesis)

As they begin to mature they become smaller in shape (nucleus/machinery disappears)

Allows more hemoglobin (HGB) to be present

HGB- protein molecule that is adapted to carry oxygen

Each RBC will have about 280 million HGB molecules

Each HGB molecule consists of 4 large globin proteins (each contains heme center (iron containing))

Anemia- condition where there is insufficient RBC (hemoglobin) in quantity/quality

Often results from low iron intake/ sometimes of autoimmune diseases/blood loss/ lack of production of RBC in bone marrow

Polycythemia- opposite of anemia (excess of RBCs)

Can occur in response to hypoxia/response to shots of EPO/dehydration.

Iron deficiency anemia- (most common in U.S.) low iron levels in body

Menstruating women- this happens most often with them (20%)

Only about 2% of men have this type of anemia

Hemorrhagic anemia- pretty dramatic and traumatic

Result of very fast and sudden blood loss (Decrease in hematocrit levels and HGB content and low RBC count)

Sickle-cell disease- autosomal recessive disorder (genetic)

Defect in DNA sequence which causes production of a faulty HGB chain (beta chain in particular) – RBC take on a very rigid and sickle-cell shaped

This makes it difficult for RBC to fit through tiny capillary beds/ less oxygen carried

Shortened life expectancy

RBC life cycle-

About 2 million cells a second created/destroyed

RBC life span Is about 120 days

Ruptured Red blood cell removed from circulation- death and phagocytosis Found in lymphatic tissues (spleen and liver) When it’s broken down its product is recycled. The recycled bits are used in formation of brand new blood cells

1) Red blood cell death and phagocytosis (macrophage in spleen/liver/ or red bone marrow)

2) Heme in HGB3) Globin is broken down into amino acids4) Iron is removed from Heme portion that forms Fe3 (associated with transferrin)- serves

as transporter for iron in the blood stream5) Microphages from spleen and liver detach Fe3 from transferrin that becomes ferritin

(iron storage proteins)6) Release from storage site or absorption from GI tract- more Fe3 attach to transferrin

7) The iron-transferrin complex carried to red bone marrow (where RBC precursor cells take up Fe3- transferrin complex through receptors through endocytosis)Take in complex and used in HGB synthesis (iron is needed to add to heme group in HGB- amino acids form globin in HGB) (Vitamin B12 is needed for this as well)

8) Erythropoiesis happens in red bone marrow (these RBC enter into circulation)9) Iron removed from heme group, then non-iron portion of heme converted into

billiverdin (green pigment) then converted into bilirubin (yellowish pigment) (bilirubin is put into blood and transported to liver)

10) ) (bilirubin is put into blood and transported to liver)11) Bilirubin in transported from liver into bile12) From small intestine into large intestine (bacteria converts it into urobillinogen) (some

urobillinogen is converted back into blood and converted into urobiligen that is secreted into urine)

13) Converted into stercobilin (brownish color) gives feces its brownish color

White blood cells (WBCs) - 5 different kinds (with varying functions) (leukocytes)

They have nuclei (unlike RBC) and other organelles like in most cells

Has no HGB (no oxygen carrying)

Divided into 2 different groups (whether or not they have chemical filled granules in their plasma membranes) (we can stain the cells to see if they have them)

Granulocytes- Have chemical filled granules in plasma membrane

Eosinophil- (2-4% of all leukocytes) Phagocytize antigen-antibody complexes. Also destroy some types of a parasitic worms

Basophil- (1/2-1% of all leukocytes) Release histamine and other chemical defenses. Play a role in allergic reactions. When basophils leave the bloodstream and enter the tissues, they are called mast cells.

Neutrophil- (60-70% of all leukocytes) phagocytic cells. Destroy bacteria

Agranulocytes- No chemical filled granules

Lymphocyte- (20-25% of all leukocytes) several subtypes exist. Two subtypes, B cells and T cells, make antibodies as part of the specific immune response. Other subtypes kill a wide variety of microbes. Others are helper cells, aiding in antibody production. (Lymphocytosis- increase in number of them- can be able to see if there are viral infection if cell count goes up) (Includes fluid lymph in lymphatic system and in blood)

Monocyte- (3-8% of all leukocytes) Leave the bloodstream and enter the tissues, where they are called macrophages. Primarily act as phagocytic cells. (Very numerous in peripheral tissues)

Leukocytosis- any amount of WBC more than 10,000 per ml cubed can indicate infection or cancer (elevation in WBC count)

leukopenia- WBC count of less than 5,000 per ml cubed (usually indicated some sort of severe disease, like AIDS, Bone marrow failure, Severe mal-nutrition, or as a result of Chemotherapy)

WBC Differential- a more specific diagnostic test where we break the 5 different blood cells into their specific percentages

Platelet- formed by really large cells (megakaryocytes- splinter into thousands of fragments)

Happens when there in the Red bone marrow

Each splintered fragment is called a platelet (enclosed inside plasma membrane)

-Leave red bone marrow and enter into circulation as an irregularly shaped disc

Many vesicles but no nucleus

In general platelets have a short life span (5-9 days) not much mass to them

Little specs interspersed among many RBCs

Important because they have granules on membrane that when they are released assist in blood clotting

Hematopoiesis- process of formed elements in blood forming

Cells formed in Red bone marrow by pluripotent stem cells

Mature in bone marrow/lymphoid tissues (thymus/spleen/tonsils/lymph nodes)

Pluripotent stem cells- the beginning of all other Red bone marrow cells

Erythropoiesis- specifically dealing with production of RBCs

Increase in state of hypoxia (low oxygen concentration) stimulates kidneys to release protein-Erythropoietin (EPO) - circulates in red bone marrow (helps speed up maturation and release of immature RBCs)

Thrombopoetin- hormone released that shows a lot of promise in stopping the depleting of platelets (depleting of platelets- side effect of chemotherapy)

Plasma

Makes up about 55% of blood

It is made up of formed elements

Mostly water

Has electrolytes/hormones/proteins/dissolved gases/glucose/ other nutrients

Albumin- major protein found in plasma (simple water soluble protein- synthesized in liver- contributes the viscosity of blood- helps body to maintain blood pressure)

Can be a transport molecule (transport qualities)

Globulins- act a transporters

Alpha globulins- carry steroids/ bilirubin

Beta globulins-carry copper and iron

Gama globulins- (immunoglobulins) antibodies

Hemostasis-

Three mechanisms reduce blood loss (has to be fast and localized and carefully controlled on damaged region)

1) Vascular spasm- occur when a damaged blood vessel constricts

Constriction slows blood flow

2) Formation of a platelet plug- platelets adhering to damaged epithelial tissues of blood vessel (form a plug and prevent blood from passing through that area quickly)

a. Platelet adhesion- platelet sticks to damaged vessel b. Platelet release reaction- helps activate the platelets (characteristics change-

many projects that help increase surface area- allows more arrow to have contact with other substances within blood)

c. Platelet aggregation- platelets become sticky (stick to each other) Accumulation of platelets- once they build up a large enough mass they form the plug that slows down blood flow to area)

3) Blood clotting (coagulation)- coagulation factors activated in sequence (result in a cascade of reactions)

Common pathway- clotting factors start off as soluble then become insolubleOne of the goals is to produce fibrin threads Consolidation of fibrin threads Is called a clot reactionAs the clot reacts the fibrin threads act to pull damaged vessel together

(decreases risk for more damage to occur/repairs vessel lining)Clots have a tendency to enlarge

Fibrinolitic system- dissolve small or inappropriate clots (dissolves clots where we have had damage after damaged is repaired)

a. Extrinsic pathway (shorter- very few steps- occurs rapidly- within seconds)b. Intrinsic pathway (more complex- responds a little more slower- responds to

damaged epithelial cells and there reaction with the platelets)

Thrombosis- clotting in an unbroken vessel (usually a vein)

Clot is called the thrombus (form for a lot of reasons- sometimes they can be caused by roughened endothelial cells in blood vessels atherosclerosis/trauma/infection)

Embolus- when a blood clot (air bubble/ piece of fat/ other debris) is transported by blood stream. (What happens after a thrombus is dislodged and starts to move around circulatory system)

Pulmonary embolism or stroke- emboli obstruct blood vessels

Blood transfusion- process of transferring blood from one person to another.

Fractionated- allows us to break blood up into its units (RBC/ Plasma/WBC/Platelets)

Can pull out individual proteins (Albumin/coagulation factors/antibodies)

Serum- liquid part of blood coagulated

Way we refer to plasma without clotting factors

We might need it so it won’t coagulate in machine to test blood

Antigens (surface markers) RBC have proteins that are associated with its surface

Proteins act as Antigens (ways we can identify different kinds of cells)

Antigens from one individual are not necessarily compatible with another individual

AB Antigens- we can determine if a cell has A or B antigens

ABO Blood Group System

RH Antigens- another important group because 85% of population usually has them (15% doesn’t have them)

Universal recipients- Type AB (because neither A or B antibodies in serum)

Universal donors- Type O (RBC have no antigens on surface)

Blood typing- done with a few drops of blood with different antibodies to see how it reacts

Agglutination- with anti-serum (indicates the presence of one of the antigens on the RBC)

Rh incompatibility- normally blood plasma will not contain anti Rh antigens

Individuals who have Rh antigens are Rh positive

It can cause problems in a blood transfusion if you are incompatible

Most common reason to screen for it involved crossing over of antigens during pregnancy (it can result in hemolytic disease of the newborn- Rh positive baby is developing in an Rh negative women)

Hemolysis- what happens in a blood transfusion if a recipient gets the wrong type of blood

Refers to the rapid destruction of the RBC

Would result in fever/ serious renal failure/ shock

Most common cause is clerical error

CHAPTER 20

THE HEART

The pump of the circulatory system

In an average human, it’s the size of the fist

Beat 10,000 per day (300,000 times a month)

Heart and vessels are important for transporting blood/constituents of blood

Circulatory system is useful for regulating body temperature/blood pH/facilitating functions of immune system

Mediastinum- where heart is located (extends from sternum posteriorly to vertebral column/ lies medially to 2 lungs)

Heart is located in middle mediastinum

Most of hearts mass is located just left of midline

Base of heart is tipped medially and posteriorly

Apex is project inferiorly and laterally

Pericardium- around the heart (membrane that surrounds the heart)

Holds the hearts position in the mediastinum

Allows room to move for the heart to expand and contract

Fibrous pericardium- dense and non-flexible tissue (protect and anchor the heart

Serous pericardium (inner layer of pericardium) (parietal layer and visceral layer)

Parietal layer- adhering to fibrous pericardium

Visceral layer- touching the heart muscle

Space between visceral and parietal pericardium (pericardial fluid- helps keeps heart lubricated so it can move around in the fibrous sac)

Myocardium- actual heart muscle

Epicardium- (most superficial layer) a thin and transparent outer layer of the heart wall (synonymous the visceral layer of serous pericardium)

Myocardium- (middle layer) thick layer composed of cardiac muscle

Endocardium- (deepest layer) thinner layer than myocardium, made of simple squamous epithelium (endothelium)

Endothelium- continuous with veins and arteries in circulatory system

Chambers of the heart

There are 4 chambers

Atria- upper 2 chambers (right and left)

Ventricles- lower 2 chambers (right and left)

Right heart- superior and inferior vena cava brings blood back to heart into right atria (deoxygenated blood) - goes to right ventricle through the tricuspid valve into pulmonary artery (carrying deoxygenated blood) to the lungs. This blood becomes oxygenated and comes back to heart (in pulmonary vein- newly oxygenated)

Blood leaving the heart the right ventricle- through pulmonary artery (deoxygenated)

Travels back to the heart in pulmonary vein (oxygenated blood)

Left heart- comes into the left atrium to the left ventricle through bicuspid valve to the atrium to the rest of the body.

Left ventricle has more muscle (because right ventricle only pumps blood to lungs, however blood from left ventricle goes to the rest of circulatory system)

Top part of the heart- considered a relatively weak pump (consists left and right atria)

Preloading from atria that is called atrial kick before the ventricles enter a contraction

Bottom part of the heart- left and right ventricles (main chambers that send blood to pulmonary circuit or systemic circuit)

Even without atrial function there is passive movement of blood going into ventricles (gravity)

Atrial kick- responsible for about 20% of increase of blood flow

Chronic atrial fibrillation- no atrial kick (common condition as people get older)

Blood flows from high pressure to low pressure

In our bodies is dictated by pressure differences- these operate the valves of our heart

Valves open in pairs

Atrioventricular valves (AV valves) –when they are open they allow blood to flow from atria to ventricles

Outflow (semilunar) valves- allow blood to flow from ventricles through outflow vesicles (pulmonary artery or aorta)

Right AV valve- (Tricuspid valve) - it has 3 little cusps- connects right atria to right ventricle

Left AV valve- (Mitral valve) - a.k.a bicuspid valve- connects left atria to left ventricle

Right outflow valve (pulmonary valve) - positioned at the entrance to pulmonary trunk that becomes the pulmonary artery

Left outflow valve (aortic valve) - open from left ventricle into aortic arch

To prevent damage of heart valves the AV valves are tethered to wall of ventricle by cordae tendinae (attached to papillary muscles)

Papillary muscles- pull on AV valves via cordae tendinae

Outflow valves (semilunar valves) - have firm cusps that look like half moons

Each cusp makes up about a third of a valve

Arteries- vessels that are directing blood away from heart (most often arteries contained oxygenated blood) (except pulmonary arteries)

Thick muscular walls (because they allow arteries endure high pressures and high forces that are exerted on them)

Veins- vessels that bring blood back to the heart (deoxygenated) (most veins are thins walled and exposed to low pressures and minimal forces acting on them)

Valves in veins work from pressure produced in body to return blood back to heart

Major Arteries-

Arch of Aorta- right of off heart

Pulmonary trunk- left and right pulmonary arteries come off of it (carry blood from right ventricle to lungs)

Coronary Arteries- supply heart muscle itself with oxygenated blood

Major Veins-

Inferior/superior vena cava- bring blood from body into right atrium

Pulmonary Veins- bringing blood from lungs back to heart (oxygenated blood)

Coronary sinus- found on back of the heart

Systemic Circuit- take blood from aorta into systemic arteries

Systemic circulation powered mostly by left side of heart (left ventricle)

Left ventricle is highly musclularized so it can happen

Pulmonary Circuit- powered by right side of heart

LOOK AT SCHEMATIC ABOUT BLOOD FLOW

Left and right coronary arteries-

LCA (left coronary artery)

RCA (right coronary artery)

Coronary veins- blood collects in coronary sinus- empties into right atrium (where deoxygenated blood joins in right atrium)

Gap junctions in intercalated discs- cells connecting and communicating to each other through gap junctions (found in intercalated discs)

Cardiac muscle is striated- the fibers are shorter and they branch- only one nucleus

Cardiac conduction system- during development a network or pathway developing (specialized myocytes- muscular cells- they are special because they have the ability to spontaneously depolarize)

Autorhythmicity- the rhythmical electrical activity that myocytes produce (important because it doesn’t need central nervous system to sustain action- no need to think about pumping the heart)

Once one group of myocytes reaches their threshold, an action potential is generated (then all of the cells in that region of the heart depolarize)

Forming the conduction system- myocytes form the conduction system of the heart and act as pacemakers in that system

Sinoatrial (SA) node- normal pacemaker of heart (located in right atrial wall, just below where the superior vena cava enters into right atria)

Spontaneous depolarization happens every .8 seconds

Moves from SA node to AV node

Once at AV node the signal is slowed (allows atrium to move blood into ventricles)

At AV noted, the electrical signal passes through AV bundle- heads towards apex of heart

(Divided into left and right branches) then spread to perkinje fibers

Perkinje fibers- rapidly conduct Action potential through ventricles (.2 seconds after AV contraction)

Each functional unit is called a functional syncytium

Atrial muscle syncytium contract as a single unit (forces blood into ventricle)

Syncytium of ventricles contracts- starts at apex and squeezed upward and exits through Aortic Valve

Autonomic nervous system Innervation-

Many sympathetic and parasympathetic points of innervation

Many alter heart rate and heart contraction

Role of ANS is to regulate changes in blood pressure/blood flow/blood volume

To put out enough blood to fill all the organs at one time

Medulla- cardio exceletory center- where there is sensory information going here (collected from carotid arteries- takes information about blood pressure and blood flow)

Sympathetic nerves are presented throughout the atria (especially in SA node and ventricles)

In addition to cardio exceletory center, there is a cardio inhibitor center (baroreceptor information comes from peripheral baroreceptors) When stimulated the parasympathetic fibers travel along vagus nerve (release ACh- decrease heart rate and force of contraction)

LOOK AT SCHEMATIC IN BOOK

Cardiac Action Potentials-

Action potential is initiated by SA node- travels through conduction system to excite working contractile muscles (found in atria and ventricles)

Action potential propagating throughout heart via opening of sodium and potassium channels

The refractory period in cardiac muscle is longer than contraction itself

Another contraction cannot being until relaxation is under way (so the heart can check and balance itself)

Blood flow would stop if there was a maintained contraction.

Mechanism of contraction is same as skeletal muscle (Sliding filament theory)

The electrocardiogram (ECG)

A way for us to monitor or record electrical changes on surface of body

Records depolarization and repolarization of myocardium

Can measure the presence or absence of certain waveforms (can measure side and time intervals of waves)

By taking an ECG we can quantify the electrical activity of heart (normal or abnormal ECG rating)

P wave- major wave deflection (atrial depolarization)

P-Q interval- time it takes for the atrial kick to fill ventricles

Q-R-S complex- tells information about ventricular depoliorization

Q wave-

R wave-

S wave-

T wave-