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Lecture 19 Where is the heart located? What is this space called? Located between the right and left pleural sacs within the thoracic cavity Space called = Mediastinum What are the 3 tissue layers of the heart? What is the histology of each layer? What is the function of each layer? •Pericardium/epicardium Function: produces serous fluid to reduce friction Histology: Dense irregular connective tissue •Myocardium Function: pumps blood Histology: Cardiac Muscle •Endocardium Function: decreases friction of blood cells against heart walls Histology: simple squamous epithelium
Know the blood flow through the heart, including the chambers, valves, and associated vessels. Where is the blood deoxygenated within the heart/vessels? Where is it oxygenated? Deoxygenated Blood Enters Right Atrium ⇩ Passes Through Tricuspid Valve ⇩ Right Ventricle ⇩ Through Pulmonary Semilunar Valve ⇩ Pulmonary Trunk ⇩ Right & Left Pulmonary Arteries ⇩ Lungs (Becomes Oxygenated) ⇩ Pulmonary Veins ⇩ Left Atrium ⇩ Through Bicuspid Valve ⇩ Left Ventricle ⇩ Aortic Semilunar Valve ⇩ Aorta ⇩ Cardiac Muscle and Other Organ Systems Know the cardiac cycle Systole vs. diastole •Systole Atria are relaxed→ blood enters both atria Ventricles contract→ blood leaves ventricles Atrioventricular valves are closed, Semilunar valves are open •Diastole Atria contract→ blood leaves both atria Ventricles are relaxed→blood fills the ventricles, Atrioventricular valves are open, Semilunar valves are closed
How do the three tissue layers differ between arteries and veins? Veins Arteries Tunica Interna less connective tissue more connective tissue Tunica Media less smooth muscle more smooth muscle Tunica Externa slightly thicker less thick What is the function of venous valves? Venous valves→ prevent backflow, especially in veins below the heart Why are valves not found in arteries? Arteries don’t have valves because the blood is being pushed under higher pressure. *How do capillaries differ in structure (think about the histology) from other blood vessels? They consist of one cell layer → tunica interna Composed of → simple squamous epithelium (endothelium) What is the function of the capillaries? Permits the diffusion of O2/CO2, nutrients, and wastes to/from adjacent tissue cells What are precapillary sphincters? Layer of smooth muscle wrapped around a capillary at the entrance to a capillary bed How do precapillary sphincters determine whether or not a tissue/capillary bed receives blood? Open when CO2 levels increase and close when CO2 levels decrease or from sympathetic stimulation What blood vessels are a part of the pulmonary circuit?
- Pulmonary trunk/arteries
- Capillary network
- Pulmonary veins Know which gasses are being exchanged by capillary network surrounding the alveoli of the lungs. Capillary Network→CO2 released and O2 taken up
What are the functions of the systemic circulation? Delivers oxygen/nutrients throughout the body to all organs Returns CO2 (and other waste products) to the heart and lungs What is the function of hepatic portal circulation? ● stores, modifies, or detoxifies substances from the GI tract ● adds plasma proteins and glucose to the blood What “type” of blood exits the hepatic portal system/hepatic portal vein? Nutrient rich/oxygen poor blood Lecture 21 What are the general functions of the blood?
- O2/CO2 transport and exchange
- Nutrient and waste transport
- Hormone transport
- Coagulation (blood clotting
- Thermoregulation (blood is diverted to/from skin controlling heat loss/gain)
- Antibody circulation (provides immunity and fights infection What are the 4 main components of blood?
- Plasma
- Platelets
- Red blood cells
- White blood cells What are the components of plasma?
- -90% water
- Cell nutrients (simple sugars, amino acids, lipids)
- Wastes (urea, ammonia)
- Hormones
- Blood gasses (CO2 and O2)
- Plasma proteins What plasma proteins are found in the plasma? What is the function of each? ● Albumin→ maintains osmotic pressure ● Globulins→ antibodies and element transport ● Fibrinogen and prothrombin→blood clotting What is the main function of red blood cells & hemoglobin? red blood cells→Allows for efficient diffusion hemoglobin→ found within red blood cells, heme/red iron containing pigment→ carries O
● Lymphocytes ● Lymphatic tissues and organs (includes lymph nodes) What are the general functions of the lymphatic system?
- Produce, maintain, and distribute lymphocytes
- Receives fatty food products from the small intestine
- Filter and return lost fluid (lymph) to the bloodstream
- provides an alternate route for the transport of hormones, wastes, and nutrients. *How do lymphatic capillaries differ from blood capillaries? How are they similar to blood capillaries? lymphatic capillaries are closed at one end, blunt ended. similiar→same histology and both permeable Why can interstitial fluid enter the lymphatic capillaries but not exit them? Margins of the endothelial cell membranes push into capillary lumen which allows fluid to enter but not exit What are lacteals? special types of lymphatic capillaries *What “materials” do the lacteals carry? What is the special name for this fluid? Lacteals pick up interstitial fluid, dietary lipids, and lipid-soluble vitamins special fluid→chyle How are lymphatic vessels similar to the blood vessels? How are they different? Similarities→contain the same 3 tunics Differeces→ lymphatic vessels are very thin and tunics are much more permeable and thinner What structure prevents the backflow of lymph? lymphatic vessels contain many valves that prevent backflow Lymph renters the blood stream via what two ducts? These two ducts carry lymph from what regions of the body? ● Thorcaic Duct→ carries lymph from the entire left and lower right side of the body ● Right lymphatic Duct→ carries lymph from the upper right side of the body only What is lymph composed of? ● Interstitial fluid ● Lymphocytes ● Macrophages ● Platelets and fat globules
What is interstitial fluid? Reabsorbed tissue fluid similar to plasma but with lower concentration of proteins ,has filtered through the capillary walls and entered the loose connective tissue surrounding the capillaries *What is specific immunity? antibodies that specifically bind to their antigens What type of white blood cell is responsible for producing this specific immunity? Lymphocytes What are the 3 types of lymphocytes?
- T-lymphoctes
- B-lymphocytes
- Natural killer cells What are the 3 types of T-lymphocytes? What are the functions of each cell type?
- Cytotoxic → kill “tagged” cells
- Helper→ release cytokines, help b-cells produce antibodies
- memory→ provide immunity against previous invaders What is the function of B-Lymphocytes? produce antiBodies What is the function of Natural Killer Cells? attack infected body cells, foreign cells, and cancer cells What are lymph nodes? Where might they be found in the body? What are their functions? small, bean shaped organs along the lymphatic pathway location→abundant in cervical, axillary, and inguinal regions function→contain macrophages to filter antigens, bacteria, foreign debris, and cell fragments; produce lymphocytes What are the 2 main functions of the tonsils?
- manufacture lymphocytes
- guard the oral and nasal entrances to remove pathogens that enter the pharynx in air/food What is the main function of the thymus? Manufactures/distributes active T-lymphocytes Where is the spleen located? What is the function of the red pulp? The white pulp?
Where are the olfactory receptors located? within the nasal cavity, connect to the olfactory bulb via cribriform plate What structures does the pharynx connect? •connects the nasal cavities and mouth with the larynx and esophagus What are the 3 subdivisions of the pharynx? What structures are found in each?
- Nasopharynx •pharyngeal tonsils •uvula •opening of pharyngotympanic tube
- Oropharynx •Palatine tonsils •Lingual tonsil
- Laryngopharynx •Esophagus •Trachea What is the histology of the lining of the upper respiratory/lower respiratory tract? mucus membrane consisting of ciliated pseudostratified columnar epithelium What are the functions of the goblet cells and the cilia? Goblet cells→secret mucus to trap airborne particles Cilia→move particles out of the body What are the 2 main functions of the larynx?
- organ of voice production
- diverts food into the esophagus What are the 4 cartilages found in the larynx? What are the functions of each? *Remeber that all of them have hyaline cartilage except for the E piglottis→ E lastic cartilage
- Thyroid cartilage •provides structural support and a site for muscle/vocal cord attachment
- Epiglottis •Covers glottis during swallowing
- Cricoid Cartilage •provides structural support
- Arytenoid Cartilage •site for vocal cord attachment How do the vocal cords produce speech?
As air moves along the folds, they vibrate, producing sound/speech What is the glottis? opening between the vocal cords *What structures does the trachea connect? Know the histology of all components of the trachea. bronchio tree with the larynx •posterior portion is composed of smooth muscle tissue •Lumen is supported by C-shaped hyaline cartilage and joined by dense irregular connective tissue Why is the posterior aspect of the trachea composed of smooth muscle tissue? it allows for expansion of the esophagus and contraction of the trachea during coughing/sneezing *Know the bifurcation of the bronchi and bronchioles. Primary,Secondary, etc. Primary bronchi ↓ Secondary bronchi ↓ Tertiary bronchi ↓ Terminal bronchioles ↓ Respiratory bronchioles
