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Contrast the definitions of endocrine gland and exocrine gland
Endocrine glands secrete substances into the internal environment.  Exocrine gland secretions are released externally.
Explain the specificity of a hormone for its target cell.
A hormone is a secreted biochemical that affects the functions of another cell.  A target cell is a cell that possesses specific receptors for a particular hormone.  Thus, a hormone affects only its specific target cell.
 
List six general functions of hormones
1. Help regulate metabolic processes.
2. Control rates of certain chemical reactions.
3. Aid in transporting substances through membranes.
4. Help regulate water balance and electrolyte balance.
5. Role in reproduction, development, and growth.
6. Help regulate blood pressure.
Explain how prostaglandins  are similar to hormones and how they are different
Prostaglandins are paracrine substances that are very potent and are only synthesized just before they are released. They are then rapidly inactivated. Some prostaglandins regulate response to hormones by either activating or inactivating cAMP production. Others can relax smooth muscle in the airway passages and blood vessels, causing dilation. Still others contract smooth muscle in the uterus causing menstrual cramps and labor contractions. Prostaglandins can also stimulate secretion of hormones from the adrenal cortex and inhibit secretion of hydrochloric acid in the stomach. Prostaglandins also influence sodium ion movement and water in the kidneys, regulate blood pressure, have power effects on reproductive physiology, and promote inflammation in damaged tissues.
Diagram the three mechanisms that control hormone secretion, including negative feedback.
In the negative feedback system, an endocrine gland or controlling system is sensitive to the concentration of substances it regulates or of a product it controls. When the concentration increases to a certain level, the gland is inhibited (a negative effect), and its activity decreases. When the concentration decreases to a certain level, the gland is no longer inhibited and its production increases. The rapid response of this system keeps hormone levels relatively stable.
Mechanisms include:
1. Control of anterior pituitary gland secretions by the hypothalamus.
2. Stimulation of some glands directly by the nervous system.
3. Direct response by other glands to changes in the composition of the internal environment.
Describe the location and structure of the pituitary gland
The pituitary gland (hypophysis) is about one centimeter in diameter and is attached to the hypothalamus at the base of the brain by the infundibulum. It is surrounded and protected by the sella turcica of the sphenoid bone. The pituitary gland is divided into two distinct lobes: the anterior (adenohypophysis) and the posterior (neurohypophysis).
List the hormones that the anterior pituitary secretes
The anterior pituitary gland secretes growth hormone (GH), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL).
Explain two ways that the brain controls pituitary gland activity
The posterior lobe of the pituitary responds to nerve impulses from the hypothalamus. Primarily the releasing hormones from the hypothalamus control the anterior lobe of the pituitary. It does this by sending the releasing hormones in the blood through a capillary network in the hypothalamus, which merges to form the hypophyseal portal veins. It passes downward into the capillary network in the anterior lobe. Substances released from the hypothalamus are sent directly to the anterior lobe.
Releasing hormones come from which one
hypothalamus
Match the following hormones with their actions:
1. Growth hormone—
2. Thyroid stimulating hormone—
3. Prolactin—
4. Adrenocorticotropic hormone—
5. Follicle-stimulating hormone—
6. Luteinizing hormone—
1) growth hormone b. cell division
2) thyroid stimulating hormone c. metabolic rate
3) prolactin a. milk synthesis
4) adrenocorticotropic hormone e. controls secretion of adrenal cortical hormones
5) follicle-stimulating hormone d. acts on gonads
6) luteinizing hormone d. acts on gonads
Explain how growth hormone produces its effects.
Growth hormone (GH), or somatotropin (STH), is a protein that causes cells to increase in size and mitotic rate. It increases protein synthesis and amino acid movement through cell membranes. GH also increases cellular respiration of fats by decreasing metabolism of carbohydrates.
Describe the control of growth hormone secretion.
Growth hormone is especially secreted during sleep, and during low blood concentrations of proteins and glucose.
 
Describe the anatomical differences between the anterior and posterior lobes of the pituitary gland
The anterior lobe is composed of layers of epithelial tissues grouped around many blood vessels. The epithelial tissues contain five types of secretory cells responsible for hormone production: mammatropes, somatotropes, thyrotropes, corticotropes, and gonadotropes. The posterior pituitary lobe is made of pituicytes and nerve fibers originating in the hypothalamus.
Name and describe the functions of the posterior pituitary hormones.
Special neurons in the hypothalamus actually produce the two hormones associated with the posterior pituitary lobe. These hormones are stored in secretory granules at the ends of their axons, in the posterior pituitary lobe.
The two hormones are:
Antidiuretic hormone (ADH)—ADH is a short polypeptide that inhibits water excretion from the kidneys.
ADH can also have a contracting effect on blood vessels. This can cause a rise in blood pressure. This is especially important in cases of severe blood loss, when ADH is needed to help increase vascular resistance. For this reason, ADH is sometimes called vasopressin.
Oxytocin (OT)—OT is a short polypeptide that is responsible for uterine contractions of labor in childbirth and contracting cells of milk glands in lactating breasts so that milk is forced out during suckling. To a lesser extent, OT can play a role in antidiuretic mechanisms.
Under which of the following conditions would you expect an increase in antidiuretic hormone secretion?
an individual is rescued after three days in the desert without food or water
Describe the location and structure of the thyroid gland
The thyroid gland consists of two large lobes connected by a broad isthmus. It is found just inferior to the larynx, bilaterally and anterior to the trachea. It is a very vascular structure encapsulated in connective tissue.
The gland is composed of many secretory follicles. The follicles are lined with a single layer of cuboidal epithelium and are filled with a clear viscous glycoprotein called colloid. Extrafollicular cells (C cells) are found just outside the follicles.
Match the hormones from the thyroid gland with their descriptions.
1. Thyroxine—
2. Triiodothyronine—
3. Calcitonin— 
1. thyroxine c. has 4 iodine atoms
2. triiodothyronine a. most potent at controlling metabolism
3. calcitonin b. regulates blood calcium
Describe the location and structure of the parathyroid glands
The four parathyroid glands are located on the posterior surface of the thyroid gland, two on each side, arranged in a superior-inferior fashion. The parathyroid gland is a small yellowish-brown structure composed of many tightly packed secretory cells encapsulated in a connective tissue layer.
Explain the general function of parathyroid hormone
Parathyroid hormone (PTH) is also called parathormone. It is a protein that increases blood calcium ion levels and decreases blood phosphate ion levels by acting on the bones, kidneys, and intestines.
 
Distinguish between the adrenal medulla and the adrenal cortex.
The adrenal medulla is the central portion of an adrenal gland and consists of irregularly shaped cells grouped around blood vessels. These cells are modified postganglionic neurons that are directly linked to the preganglionic autonomic nerve fibers leading from the central nervous system.
The adrenal cortex is the outermost part of an adrenal gland and makes up the bulk of the gland. It is made of closely packed masses of epithelial layers that form three distinct zones: the zona glomerulosa, zona fasiculata, and zona reticularis—the outer, middle, and inner layers, respectively.
Match the adrenal hormones with their source and actions:
1. Cortisol—
2. Aldosterone—
3. Epinephrine—
4. Androgens—
5. Estrogens—
1. cortisol e. cortex; gluconeogenesis
2. aldosterone a. cortex; sodium retention
3. epinephrine d. medulla; fight or flight response
4. androgens c. cortex; male sex hormones
5. estrogens b. cortex; female sex hormones
Describe the location and structure of the pancreas
The pancreas is an elongated, flattened organ posterior to the stomach and the parietal peritoneum, and is attached to the duodenum by a duct. Structurally, the pancreas is composed of grouped cells called islets of Langerhans that are closely associated with blood vessels. The islets of Langerhans contain three types of cells: alpha, beta, and delta cells.
List the hormones the pancreatic islets secrete and their general functions
Glucagon—Glucagon is a protein secreted by alpha cells and is responsible for converting glycogen into glucose (glycogenolysis) in the liver, and noncarbohydrates into glucose (gluconeogenesis). Glucagon also stimulates the breakdown of fats into fatty acids and glycerol.
Insulin—Insulin is a protein secreted by beta cells that has the opposite effect of glucagon. In the liver, it stimulates formation of glycogen and inhibits conversion of noncarbohydrates. Insulin also promotes facilitated diffusion of glucose through the membranes of insulin target cells.
Somatostatin—Somatostatin is secreted by delta cells and inhibits glucagon and insulin secretion and helps regulate carbohydrates.
Describe the location and general function of the pineal gland
The pineal gland is small and oval, found deep between the cerebral hemispheres, and attached to the upper portion of the thalamus near the roof of the third ventricle. It is made up of pineal and neuroglial cells. The pineal gland secretes melatonin in response to periods of decreased light. It is believed that this aids in the regulation of circadian rhythms and inhibiting gonadotropins from the anterior pituitary gland. It may also help to regulate menstrual cycles.
Describe the location and general function of the thymus.
The thymus gland begins in childhood as a large substernal gland found in the mediastinum between the lungs, but diminishes in size with age. It plays an important role in immunity by secreting a group of hormones called thymosins that affect production of T lymphocytes (white blood cells).
Name five additional hormone-secreting organs
1. Ovaries
2. Placenta
3. Testes
4. Small intestine
5. Heart
6. Kidneys
7. Stomach lining
Distinguish between a stressor and stress
Stress is a condition in which potentially life-threatening changes occur in the body’s internal environment. To maintain homeostasis, the body must react to counter these changes. A stressor is any factor that can cause these conditions.
List several factors that cause physical and/or psychological stress
Extreme temperatures, decreased oxygen, infection, injuries, heavy exercise, and loud noise can cause physical stress. Psychological stress differs from person to person but typically includes personal loss, thoughts of real or imagined dangers, unpleasant or lack of social interaction, anger, fear, grief, anxiety, depression, or guilt.
Occasionally even pleasant stimuli, such as friendly contact, joy or happiness, or sexual arousal, may cause stress.
Describe hormonal and nervous responses to stress
Nerve impulses are transmitted to the hypothalamus.  Blood glucose concentration increases, blood glycerol increases, blood fatty acids increase, heart rate increases, and blood pressure increases.  Blood is shunted into skeletal muscles.  Epinephrine intensifies.  Increased ACTH increases the level of cortisol, etc.  ADH promotes the retention of water, which increases blood volume.  Renin increases.  Aldosterone stimulates sodium retention by the kidneys. 
Levels of which hormones decrease with age?  Which increase?
Endocrine glands tend to shrink and accumulate fibrous connective tissue, fat, and lipofuscin, but hormonal activities usually remain within the normal range.
GH levels even out, as muscular strength declines.
ADH levels increase due to slowed breakdown.
The thyroid shrinks but control of metabolism continues.
Decreasing levels of calcitonin and parathyroid hormone increases osteoporosis risk.
The adrenal glands show aging-related changes, but negative feedback maintains functions.
Muscle, liver, and fat cells may develop insulin resistance.
Changes in melatonin secretion affect the body clock.
Thymosin production declines, hampering infectious disease resistance
What problems might result from the prolonged administration of cortisol to a person with severe inflammatory disease?
Prolonged cortisol administration may result in: elevated blood glucose level (diabetes mellitus); edema; hypertension (due to retention of sodium); redistribution of body fat; muscle wasting (due to protein catabolism); osteoporosis (due to loss of calcium from bones); and decreased antibody response (which would impair wound healing and increase susceptibility to infections).
Why might oversecretion of insulin reduce glucose uptake by nerve cells?
Nerve cells obtain glucose through a mechanism that is not insulin-dependent, but rather depends only on the blood glucose concentration.
Major functions of blood include

  1. Nutrient, hormone, oxygen, and waste transport

  2. Helping maintain stability of interstitial fluid

  3. Heat distribution

Formed elements in blood are ____________, ___________, and _____________.
red blood cells, white blood cells, and platelets
 
The liquid portion of the blood is called ____________.
plasma
Define hematocrit, and explain how it is determined
Hematocrit (HCT) is the percentage of the cells in a blood sample. This is obtained by allowing the sample to stand (clotting is prevented), allowing the cells to separate and sink to the bottom. This is further centrifuged and the percentage of the cells and liquid is determined.
Describe a red blood cell.
A red blood cell is a biconcave disk that has no nucleus.
 
Contrast oxyhemoglobin and deoxyhemoglobin
Oxyhemoglobin is hemoglobin combined with oxygen. Deoxyhemoglobin is hemoglobin that has released its oxygen.
Explain the significance of red blood cell counts
A red blood cell count is the number of red blood cells in a cubic millimeter (mm3) of blood.
 
Define erythropoietin, and explain its function.
Erythropoietin is a hormone that is released from the kidneys, and to a lesser extent the liver, which stimulates red blood cell production
Explain how vitamin B12 and folic acid deficiencies affect red blood cell production
Both substances are required for DNA synthesis that is needed by all cells for growth and reproduction.
Hematopoietic tissue reproduces at a particularly high rate, so this tissue is especially affected by the lack of either vitamin.
List two sources of iron that can be used for the synthesis of hemoglobin.
Obtaining vitamin C in the diet will increase iron absorption from the small intestine. It is also conserved from the red blood cell destruction and reused.
Distinguish between biliverdin and bilirubin
Biliverdin is the greenish pigment that results when the heme portion of the hemoglobin breaks apart.
Bilirubin is what biliverdin eventually converts to over time
Distinguish between granulocytes and agranulocytes
A granulocyte is a white blood cell that has granular cytoplasm. Agranulocytes are white blood cells that lack cytoplasmic granules.
Name five types of leukocytes, and list the major functions of each type
a. Neutrophils are granulocytes that function to phagocytize foreign particles.
b. Eosinophils are granulocytes that function to kill certain parasites and help control allergic reactions.
c. Basophils are granulocytes that function to release heparin that inhibits blood clotting. They also release histamine to cause inflammation.
d.  Monocytes are agranulocytes that leave the bloodstream to function as macrophages that phagocytize foreign particles.
e.  Lymphocytes are agranulocytes that function to produce antibodies that act against specific foreign substances.
Explain the significance of white blood cell counts as aids to diagnosing disease.
If there is a rise in white blood cells, there could be an infection of some type going on within the body. If the white blood cell count drops, there could be an entirely different set of diseases that could be going on within the body. A differential white blood cell count measures the numbers of each specific type of white blood cell. This can signal a specific disease process, as an increase in neutrophils usually means a bacterial infection.
____________ are fragments of megakaryocytes that function in ___________.
Platelets (thrombocytes), the formation of blood clots.
The most abundant component of plasma is: _________.
water.
Name three types of plasma proteins, and indicate the function of each type
a. Albumins—help to maintain osmotic pressure of the blood.
b. Globulins—help to transmit lipids and fat-soluble vitamins and are the antibodies of immunity.
c. Fibrinogen—precursor to fibrin that has a major role in blood clotting.
Name the gases and nutrients in plasma
Gases in plasma include oxygen, carbon dioxide, and nitrogen.  Plasma nutrients include amino acids, simple sugars, and lipids.
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