Lab Exam 3 Study Guide PDF

Renal Physiology Describe the basic components of the urinary system emphasizing their function. - Made up of kidneys, ureters, urinary bladder, + urethra - Fxn: to maintain purity + health of the body's fluids by removing toxins and recycling good substances. - The kidneys are...

Renal Physiology Describe the basic components of the urinary system emphasizing their function. - Made up of kidneys, ureters, urinary bladder, + urethra - Fxn: to maintain purity + health of the body's fluids by removing toxins and recycling good substances. - The kidneys are located behind the peritoneum, with the left kidney usually being higher than the right kidney. Understand the basic anatomy of the kidney (macro and micro). - Fxn: - Regulates plasma osmolarity, acid-base hemostasis, and energy metabolism - Detoxification through urine - Converts vitamin D3 into its active form - Synthesis + conversion of important hormones - Anatomy: Nephron: smallest functional unit of the kidney. Understand the path of renal blood flow. - Renal arteries come in and split into segmental arteries - Each segmental artery is going to split into interlobar arteries  - Interlobar arteries split off into arcuate arteries - Arcuate arteries split off into interlobular arteries + veins Explain the mechanisms of urine production. 1. Filtration: a. Happens in renal corpuscle (Bowman’s capsule + glomerulus), first step of urine production 2. Reabsorption: a. Recycle + put back in blood b. Movement from renal tubules into capillaries c. In descending limb of nephron loop; water is reabsorbed d. In ascending limb of nephron loop; sodium, chloride, and potassium are reabsorbed. e. In DCT; water, calcium, sodium, and chloride are reabsorbed. 3. Secretion: a. From blood → collecting tubule → urine b. In PCT; hydrogen ions, ammonium, creatinine, toxins, and drugs are secreted. c. In DCT; hydrogen ions + K+ are secreted **Reabsorption and secretion occur at the same time** Elaborate on the happenings of the glomerulus, PCT, loop of Henle, DCT, and collecting duct. - Glomerulus: - Initial stage of urine formation; - PCT: - Pumps Na+ ions using active transport; - Helps reabsorb much of the “good stuff”; - Vast majority of renal reabsorption occurs in the proximal convoluted tubule (PCT); - Approximately 67% of Na+ and 67% of H2O reabsorption (equal proportions = isosmotic) - 100% of glucose should be reabsorbed here in healthy individuals - Loop of Henle: - The longer the loop, the greater the counter-current multiplication - The ascending loop of henle actively pumps out salt; impermeable to water - The descending loop of henle allows to water leave - DCT: - Reabsorption: sodium, chloride, bicarbonate, and some H2O - Secretion: ammonia, K+ - Aldosterone regulates Na+ (sodium) reabsorption - Parathyroid hormone (PTH) works on DCT to stimulate Calcium (Ca+) reabsorption when it is low - Empties into collecting duct - Collecting duct: - Contains aquaprins (aid in the reabsoption of H2O into the blood) - Reabsorb Na+ - Secrete K+  Understand the glucose titration curve. - In healthy individuals, there will be 100% reabsorption of glucose in the PCT; - Plasma glucose < 200 mg/dL → all of it is being reabsorbed - Plasma glucose 200 mg/dL < x < 400 mg/dL → some of it is being reabsorbed, some isnt being reabsorbed - > 400 mg/dL → none of it getting reabsorbed Describe the physiological mechanisms of the renin-angiotensin-aldosterone system (RAAS). Low blood volume → activates juxtaglomerular apparatus → secretes renin Renin → angiotensin I → angiotensin converting enzyme (ACE) → angiotensin II → Angiotensin II releases aldosterone Understand the significance of various substances if found in the urine such as: glucose, bilirubin,ketones, blood, protein, leukocytes, etc. **CHECK LAB REPORT** Understand the importance of urine color, transparency, pH, and specific gravity. **CHECK LAB REPORT** Understand the role of ADH and aldosterone in the urinary system. - Aldosteron: - Promotes sodium reabsorption - Promotes retention of H2O and sodium - Stimulates thirst - Increases blood pressure - ADH or Vasopressin: - Increases H2O permeability in DCT and collecting duct by adding aquaporins (which increase H2O reabsorption + retention - ADH present → concentrated urine - ADH absent → diluted urine Mention the physiological components involved in the micturition reflex. Understand the fundamentals of urinary tract infections and renal calculi. Endocrine Physiology Differentiate among the primary and secondary endocrine organs. Primary organs: produce + secrete hormones as their primary role. This includes pituitary gland, adrenal gland, and thyroid gland. Secondary organs: produce + secrete hormones in addition to their primary role or function. This includes the kidneys and skin. Understand the role of hormones in relation to homeostasis & elaborate on the specific classifications. - Hormones are chemical messengers that travel through the bloodstream to their destination to then signal a specific physiological response. - These hormones travel slowly through the bloodstream. - The solubility in water determines the chemical property of a hormone. - There are two broad molecular categories of hormones: Amino acid based and steroids. - Amino acid based:  - Derived from amino acids (ie. amines, peptides, + proteins) - These are usually water-soluble (with the exception of thyroid hormone) - They also cannot cross the plasma membrane; it binds to the receptors on the surface of the cell. - Steroids: - Synthesized from cholesterol - Lipid soluble can cross the plasma membrane - The receptors for these hormones are inside the cell - This includes the thyroid hormone as well Understand the role of the hypothalamus in relation to the anterior and posterior pituitary secretions. - The hypothalamus controls the release of hormones from the pituitary glands - Anterior pituitary gland: - Primarily interacts with the hypothalamus through the hypophyseal portal system. This system has small blood vessels that flow between the hypothalamus and anterior pituitary. - Hypothalamus secretes hormones through this system. - Hormones travel through this hypophyseal portal system. - In the anterior pituitary, these hormones will either inhibit or stimulate the release of hormones - These hormones released by the anterior pituitary gland are made and secreted here. Anterior Pituitary Hormones: FLATPEG NAME TARGET TISSUE Effect/ Fxn Adrenocorticotropic hormone Adrenal cortex - secretion of glucocorticoids, (ACTH) mineralocorticoids, + androgens Thyroid-stimulating hormone Thyroid - secretion of thyroxine (T4) (TSH) and triiodothyronine (T3) Luteinizing hormone (LH) Ovaries + testes - triggers ovulation in females - testosterone production in males Follicle-Stimulating hormone Ovaries + testes - stimulates ovarian follicle (FSH) production of estrogens in females - stimulates sperm production in males Growth hormone (GH) Liver, muscle, bone, cartilage, - regulates metabolism etc. - regulates body growth Prolactin (PRL) Mammary glands - promotes lactation  - Posterior pituitary gland: - hypothalamus makes/ synthesizes hormones + delivers them to posterior pituitary gland to be stored + then released when needed. - Hypothalamic hypophyseal tract connects the hypothalamus to the posterior PG. - Hypothalamic neurons synthesize oxytocin + ADH. Posterior Pituitary Hormones: NAME TARGET TISSUE Effect/ Fxn Antidiuretic hormone (ADH) Kidneys - H2O storage, reabsorption Oxytocin Uterine smooth muscle, - love hormone mammary glands - initiates labor + stimulates contractions - initiates milk ejection while breastfeeding Understand the role of the pineal gland. - Regulates circadian rhythm. - Produces and secretes melatonin; inhibited during the day and secreted at night. - Important precursors: tryptophan (an amino acid that forms serotonin) → serotonin (a neurotransmitter that yields melatonin) → melatonin Understand the role of the adrenal glands. - Pyramid shaped gland located on top of kidney (also called suprarenal gland) - Helps us deal with stress - Adrenal cortex: - Outermost portion of adrenal gland - Releases over 2 dozen steroid hormones (collectively called corticosteroids) - There are 3 zones within this cortex: - Zona glomerulosa: - Outermost region - Secretes mineralocorticoids (ie. aldosterone) - Regulates minerals + water in blood - Zona fasciculata: - Middle region - Secretes glucocorticoids (ie. cortisol) - Stimulates glucose formation + inhibits glucose utilization - Zona reticularis: - Innermost region - Secretes gonadocorticoids (ie. DHEA) - Contributes to axillary + pubic hair formation - Adrenal → sex drive - Adrenal Medulla:  - Innermost region of adrenal gland - Part of sympathetic nervous system - Secretes epinephrine + norepinephrine - Fight or flight response Understand the role of the thyroid gland. - Butterfly shaped glands that affect almost every cell in our body! - Produces two hormones: thyroid + calcitonin - Thyroid hormone: - This is the body's major metabolic hormone - Impacts temp regulation - Released from follicular cells - T4 (thyroxine) - T3 (triiodothyronine) - Calcitonin: - Lowers blood calcium levels - Released from parafollicular cells (C-cells) - High blood Ca+ → parafollicular cells secrete calcitonin → calcitonin drops blood calcium levels by inhibiting osteoclasts + encouraging osteoblasts Understand the role of the parathyroid gland. - Small gland located posterior region of thyroid (usually two on each side) - Produces + secretes parathyroid hormone (PTH). - PTH is crucial for controlling blood calcium balance. - PTH increases calcium levels in the blood by stimulating 3 target hormones: - Skeleton: by stimulating osteoclasts we can break down some of that calcium rich matrix. - Kidneys: enhances calcium reabsorption + decreases calcium excretion, raising blood calcium levels. - Intestine: promotes activation of vitamin D, increasing calcium absorption through our diet. Understand the role of the pancreas. - Has endocrine + exocrine functions - Endocrine cells are located in islets of Langerhans - This is where the production of pancreatic hormones takes place - Contains alpha + beta cells - Alpha cells: - Secrete glucagon - This is a hyperglycemic hormone; works to raise blood glucose levels - Targets the liver to turn glycogen into glucose - Tells liver to synthesize glucose from lactic acid - Beta cells: - Secretes insulin, which lowers blood glucose levels - Does so by enhancing membrane transport of glucose - Glucose then gets put into our cells Understand the physiological mechanisms leading to diabetes mellitus. Be able to differentiate between type I and type II based on clinical presentation. Understand the importance and impact of this condition. - Diabetes Mellitus (DM) is characterized by persistent hyperglycemia - Type 1 diabetes - Occurs usually at an early age - Autoimmune disorder that destroys pancreatic beta cells; cannot secrete insulin - Not really correlated to body fat - Only about 10% of diabetic population - Type 2 diabetes - Adult onset - Non insulin-dependent - Characterized by insulin resistance - Strong correlation with body weight + obesity - About 90% of diabetic population **PTH and Calcitonin have opposite effects: - PTH raises calcium levels - Calcitonin lowers calcium levels