Lab 8: The Endocrine System & Blood rev 3/11

Lab 8: The Endocrine System & Blood rev 3/11 The Endocrine system is a system of glands which release hormones directly into the bloodstream so they can be carried to their target organs or cells • Hormones are chemical “messengers” carried by the blood to be transported throughout the body • They communicate with target cells—cells which have hormone receptors • Target cells are specific for each hormone; if a cell does not have an appropriate hormone receptor, the cell will be unresponsive to the hormone • Target cells can be compared to a radio transmitter; we tune the radio and pick up the signals of specific stations Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Defining features of hormones • Come from endocrine glands • Circulate in the bloodstream • Act only upon specific cells in the body • Endocrine glands release hormones directly into the bloodstream; they do not need ducts to help with secretion Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Hormones fall into two categories • Non-Steroid or Peptide hormones • Built from amino acids and closely resemble neurotransmitters • Steroid hormones • Are structurally related to cholesterol and are lipid (fat) soluable Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System -Blood Ways that a gland is stimulated to release hormones: 1. Humoral Control Mechanism • The cells of a gland are sensitive to changes in circulating levels of chemicals which it regulates 2. The gland may be stimulated directly by the nervous system • ANS stimulates epinephrine 3. The gland may be controlled by hormones of other glands • Pituitary hormone stimulates the ovaries Lec 8 Lec 8 Lec 8

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Lab 8-The Endocrine System Blood MAJOR ENDOCRINE GLANDS (find these glands on the model, NOT on your pig) • Hypothalamus • Controls pituitary function and release of hormones Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood • Pituitary Gland • Is connected to the hypothalamus by a narrow strip of tissue (called the infidibulum) • Is located right behind the center of the eyes • Often called the master gland because it secretes 8 different hormones and regulates many of the other endocrine glands • HOWEVER, the hypothalamus actually controls the function of the pituitary gland Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood • The pituitary gland also releases Tropic Hormones, hormones which control other endocrine glands • ACTH-Adrenocorticotropic Hormone • Stimulates the adrenal cortex to release glucocorticosteroids (steroid hormones involved in stress related conditions and the metabolism of glucose) • TSH-Thyroid Stimulating Hormone • Stimulates the gland to produce thyroxine Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Thyroid Gland • Located just below (or inferior to) the larynx at the front and side of the trachea • Produces thyroxine and calcitonin • Thyroxine contains iodine and helps regulate the rate of cellular metabolism • Calcitonin helps the body to store calcium in the bones. This works to lower blood calcium levels. Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Parathyroid Gland • Located in the back of the thyroid gland • Produces PTH Hormone (Parathyroid Hormone) which • Removes calcium and phosphate from bone • Increases absorption of calcium by the digestive tract • Increases production of vitamin D Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Adrenal Glands • Located just above the kidneys • Each gland has an outer layer, the adrenal cortex and an inner core, the adrenal medulla • You do not need to know the different tissue layers of the adrenal glands Lec 8 Lec 8 Lec 8

Adrenal Cortex produces • Aldosterone, a mineralocorticoid (mineral regulating hormone primarily sodium and potassium) • Glucocorticoids including cortisone, cortisol and corticosterone • Androgens which have a role in the development of male and female secondary sexual characteristics • Adrenal Medulla • Produces epinephrine (commonly known as adrenalin) and norepinephrine, Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Pancreas • Has groups of hormone producing cells called the Islets of Langerhans • Pancreas Hormones • Insulin allows other cells to absorb glucose from the blood and store it as glycogen • Glucagon stimulates the liver to break down glycogen into glucose so the body can use it for energy Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Gonads • The testes, in males, are located in the scrotum and produce testosterone • The ovaries, in females, are located in the pelvic cavity and produce estrogen and progesterone Thymus Gland • Located near the heart • Plays a major role in the body’s immune system Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Pineal Gland or Pineal Body • Located in the brain • Secretes melatonin which is believed to synchronize the day-night cycles of our body The Kidneys • can also function as an endocrine gland • Produce • Renin which can increase blood pressure • and Erythropoietin which stimulates RBC production Lec 8 Lec 8 Lec 8

REMINDER, Endocrine Glands: 1. You will be given a fetal pig today but we will begin to dissect it next week. There is too much we must do in today’s lab. 2. You are responsible for locating the pituitary, hypothalamus, and pineal glands on the human brain model. 3. Locate on the human model the endocrine glands listed in the diagram on page 98 of the lab manual (the thyroid, thymus, pancreas, adrenal glands, ovaries, and testes). Use Table 11.1 to learn about the endocrine glands, its hormones and the function of these hormones. Lec 8 Lec 8 Lec 8

Blood • Blood is actually a liquid body tissue and is classified as a connective tissue because its cells protect the body • it communicates with all cells of the body • capillaries are one cell thick and connect the arterial circulation to the venous circulation • because the capillaries are small and thin, molecules move freely across their walls • this allows for waste products to be exchanged for nutrients Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood • Fluid portion of blood • called plasma • plasma contains several different kinds of proteins called “formed elements” • Formed Elements of the Blood • Red blood cells, white blood cells and platelets are collectively called “formed elements” Lec 8 Lec 8 Lec 8

Red Blood Cells (RBC) or erythrocytes • contain hemoglobin, a protein which carries oxygen and carbon dioxide • RBC live for approximately 4 months. • As they mature, they expel their nucleus so they can carry more hemoglobin. • They also assume a biconcave shape. This shape makes them more flexible and allows more of them to fit into blood vessels to increase the surface area available for gas (O2 and CO2) exchange. Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood • Hemoglobin Molecule • Hemoglobin is an oxygen binding protein which consists of 4 polypeptide chains coiled around a “heme group” • The “heme group” has an iron atom in its center. This combines easily with oxygen at the lungs AND lets go of the oxygen when reaching body tissues. Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Hematocrit • is a measure of the oxygen carrying capacity of blood • is obtained by spinning down blood and measuring the amount of formed elements • RBCs make up nearly 99% of formed elements • Normal hematocrit • men: 42-52% women: 37-47% Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Anemia • refers to a deficiency in oxygen carrying capacity of the blood Types of Anemia • Pernicious Anemia • body is unable to absorb vitamin B12 from the digestive tract • the body uses B12 to produce normal RBC Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood • Sickle cell Anemia • is an inherited disorder in which the RBC become sickle or crescent shaped when the oxygen concentration of the blood is low. This shape doesn’t travel easily through blood vessels because the cells clump, get stuck in the vessels and cause a great deal of pain. • Sickle shaped cells can’t carry a normal amount of oxygen. Lec 8 Lec 8

Lab 8-The Endocrine System Blood • Iron deficiency anemia occurs when there is insufficient iron ingested. Polycythemia is a term used to describe an abnormally high RBC count • this increases the thickness of blood and slows down the flow of blood. Lec 8 Lec 8 Lec 8

REMINDER: BLOOD-RBC • Do not do the hematocrit or blood typing activity. This is no longer performed due to Hepatitis C, not AIDS Lec 8 Lec 8 Lec 8

White Blood Cells or Leukocytes Originate in the red bone marrow • Types of WBC (page 109 of lab manual) • Neutrophils-most common WBC- approximately 65% of WBC are neutrophils • see in acute infections; are the first WBC to combat infection • main function is phagocytosis • Lymphocytes-second most common WBC, about 20% • involved in immune response • manufactures antibodies and eliminates anything foreign to the body Lec 8 Lec 8 Lab 8

Lab 8-The Endocrine System Blood • Monocytes-about 8% • active in phagocytosis • elevated in chronic infections • Eosinophils-less than 5% of WBCs • see in parasitic infections • Basophils-are rare, less than 1% of WBCs • initiate the inflammatory response Lec 8 Lec 8 Lec 8

Eosinophil Basophil Neutrophil Lymphocyte Monocyte Lec 8 Lec 8 Lec 8

Figure 4-3: Types of white blood cells

Recognizing leukocytes/WBC-helpful hints • Neutrophils: have smaller paramecium shaped nuclei which are multi-lobed; cytoplasmic granules not prominent • Eosinophils: have a really red (paramecium shaped) nucleus; looks like a strawberry or bug eyes • Basophils: havelots of large cytoplasmic granules • Lymphocytes: nucleus is generally spherical; pale blue cytoplasm • Monocytes: its nucleus is U or kidney shaped; can see cytoplasm around the nucleus Lec 8 Lec 8 Lec 8

REMINDER • Use the chart on page 109 of the manual and the color charts around the room to help you identify the different types of white blood cells. • Activity on page 110 of manual -Do the drawings; they will help you recognize the differences between the WBC • Page 111-complete chart to help you further understand value of WBC Lec 8 Lec 8 Lec 8

Lab 8-The Endocrine System Blood Platelets • are small cell fragments (not complete cells) which play an essential role in the process of blood clotting • platelets are stable as they circulate, but when they encounter a “rough surface” they form a temporary plug and initiate the clotting mechanism • the body also requires vitamin K for normal blood clotting Lec 8 Lec 8 Lec 8

Clotting process • damage to a blood vessel triggers a vasospasm or constriction of the damaged blood vessel • platelets in the area swell, become sticky, adhere to the damaged area and produce a plug which will become the clot • platelets also release chemicals to help in clot formation Chemicals released: • prothrombin activator converts prothrombin (a plasma protein) into thrombin • thrombin converts the fibrinogen molecules, to fibrin which traps blood cells, forms a clot and seals the hole Lec 8 Lec 8

Blood Typing • Each of us has one of 4 types of blood--A, B, AB, O-- along with some specific glycoproteins or antigens • Our cells have surface proteins that the immune system can recognize as “self” or “non-self”. The immune system will recognize foreign cells as non-self . • An antigen is a non-self cell protein that causes the immune system to defend itself. • The immune system builds antibodies-an opposing protein which can kill the non-self cells. • and causes them to stick together so it can be destroyed. So, the transfused blood clumps or clots within our blood vessels. • This can be fatal Lec 8 Lec 8 Lec 8

Another antigen found in blood is the Rh antigen--if you have it, your blood is classified as Rh positive. If you do not have this, your blood is classified as Rh negative. Blood Typing Tests • Based on the interaction between antigens and antibodies • performed with anti-sera which contain high concentrations of anti-A and anti-B antibodies • blood samples are mixed with each anti-sera Lec 8 Lec 8 Lec 8

if clumping (similar to clotting) occurs with anti-A sera, you have type A blood anti-B sera, you have type B blood • if clumping occurs with both anti-A and anti-B, you have type AB blood • if no clumping occurs with either anti-A and anti-B sera, you have type O blood • so, the antibodies you have in your body are the opposite of your blood type Lec 8 Lec 8 Lec 8

Anti Anti Anti A B Rh Agglutination Reactions Blood Type? Not Agglutinated Agglutinated Lec 8 Lec 8 blood-cardiovascular

REMINDER 1. You need to know the background information but will not perform the activity for hematocrit and blood type (page 108). 2. Look at the wall charts, table charts, and your lab manual to see erythrocytes and recognize the different leukocytes. Note that RBC do NOT have a nucleus. • Your group will get a fetal pig today but we will not have time to begin the dissection. We will start this next week. One fetal pig will be shared by 3-4 people. Make sure that each of you participates in the dissection. • When we dissect, tie long hair back so it doesn’t mix with the pig insides when you bend down to look at the pig. Lec 8 Lec 8 Lec 8

REMINDER, page 2 of 2: 5. If you don’t remember your microscope skills go back to Chapter 1 for a review if needed. --Remember to have the microscope light on low. Blood cells are small so can be hard to see. 6. Most of the cells you will see are RBC (pale pink/orange with no nucleus). 7. When you see a cell with a nucleus, you have found some kind of WBC. Lec 8 Lec 8 Lec 8

Blood Types Determine Blood Compatibility Lec 8 Lec 8 Lec 8 Figure 7.12

Blood Typing Lec 8 Lec 8 Lec 8

Lab 8: The Endocrine System & Blood rev 3/11