Lab 15: Urinary and Endocrine Systems Flashcards
kidneys
• main structural components of urinary system
• function: excretion and maintenance of a constant internal environment
- elimination of nitrogenous wastes
- elimination excess water/salt
- conservation proteins / glucose
• retroperitoneal - covered by peritoneum only on the portion next to the abdominal cavity
urogenital system
kidneys, renal pelvis, ureters, bladder and urethra
- grouped via same location/share certain passages
urinary bladder
- pear-shaped, muscular organ
- function: temporary storage of urine.
- attached to body by mesentery and brim of pelvic canal by mesenteries.
kidney surrounded by 3 tissue layers
-what are their function?
- renal capsule (next to the kidney surface)
- middle adipose capsule
- renal fascia -(outer layer)
Function: layers help to protect the kidney from trauma and anchor it firmly in place
2 Mjor Kidney Sections
- renal cortex: light red superficial region, granular in appearance.
- renal medulla: deep to cortex, darker reddish-brown, contains cone-shaped masses called renal pyramids.
nephron
- function
- made up of
- types of nephrons
- functional unit of the kidney
- perform all phases of urine formation
- nephron = renal corpuscle + renal tubule
Types
• Cortical Nephrons: 85%, short loops of Henle, renal cortex area
• Juxtamedullary Nephrons: 15%, long loops of Henle, extend into medulla region
Renal corpuscle
= Bowman’s capsule + Glomerulus
Pathway of urine:
Start in Glomerulus until exit body
Glomerulus —> Bowman’s capsule—>proximal convoluted tubule—>descending limb —>loop of Henle—>ascending limb —> distal convoluted tubule —> collecting duct —>
Urine drains to base of pyramid (renal papillae)—> minor calyx—>major calyx—> renal pelvis—> ureter —> urinary bladder —>urethra
The nephrons are capable of producing a concentrated urine primarily through the processes of
-3
- glomerular filtration
- tubular reabsorption
- tubular secretion
Glomerular Filtration
- pass through
- retainined
- separates materials by size in relation to pores of filtration membrane
- Urine formation begins when blood enters glomerular capillaries
- Pass Through: Water, glucose, nitrogenous wastes
- Retained in Blood: blood cells, proteins, macromolecules
- Filtrate formed enters renal tubule
- glomerular hydrostatic pressure: chief force pushing water/solutes out of blood across filtration membrane
Filtration
Passive process. Fluids/solutes forced through membrane by hydrostatic pressure
Tubular Reabsorption
- Substances (Na+, Ca+, water, glucose) re-enter the blood
* Begins as soon as the filtrate enters the proximal convoluted tubule
Tubular Secretion
- Substances that were too large to filter can enter urine from the blood (H+ ions, K+, etc)
- Blood pH must be maintained at a constant level (approximately 7.4) at all times, therefore kidney excretes H+/OH-
antidiuretic hormone (ADH)
- Function
- Procuced by
- Secreted by
- When is it inhibited or release?
- Function:controls volume of urine excreted and salt concetration
- Produced: hypothalamus; Secreted: posterior pituitary gland
- ADH Release: Pain, low blood pressure, and certain drugs (nicotine, morphine, and barbiturates)
- ADH Inhibit: alcoholic beverages inhibit ADH secretion.
What happens with ADH when:
- we drink lots of water
- lose blood volume
Blood is diluted
• drink lots of water
• ADH production decreases
• large amount of dilute urine produced.
Osmotic Pressure (“saltiness”) of blood increases,
• drinking salt water / lose fluid (bleeding, sweating)
• production of ADH increases
• stimulates kidney tubules to reabsorb water from the filtrate back into the body.
• ADH is destroyed within 10 - 20 minutes after being released into the circulatory system.
Diabetes insipidus
- Deficient ADH secretion
- large amounts of urine produced
- extreme thirst.
- Can be managed with drugs/adequate water intake.
aldosterone
- hormone produced by adrenal gland cortex
- Function: maintain Na+ /K+ [ ] of extracellular fluids.
- primary target = distal kidney tubules
- stimulates Na+ reabsorption and K+ excretion.
Abnormal Urine
- pH
- blood present
- glucose present
- protein present
- Nitrites present
pH
- normal range of pH values for urine is 4.8 to 7.5
- acidic urine: diet high in protein and whole wheat
- alkaline urine: vegetarian diet
Blood
- glomerular infection, physical trauma to kidney tissues, tuberculosis, tumors of the urinary tract, kidney stones or severe burns
Glucose
-diabetes mellitus
Proteins
- glomerulonephritis or severe hypertension
- protein may also appear during pregnancy
- may appear following vigorous exercise or high protein intake
Nitrite
- bacterial infection
Specific gravity
- ratio of the mass of a substance to the mass of an equal volume of distilled water (solute : solvent)
- SG distilled water = 1.0
- urine = water + solutes
- SG range 1.005 to 1.030 (higher the number, the greater the density of the urine)
- Increase in water (in urine) = decrease in SG
What would be the expected effect of each of the following conditions?
consumption of 500 ml water on urine volume:
consumption of caffeine (a diuretic) on urine volume:
consumption of an alkaline solution on urine pH:
vigorous exercise on urine volume:
vigorous exercise on the specific gravity of urine:
consumption of 500 ml water on urine volume:
- increase
consumption of caffeine (a diuretic) on urine volume:
- increase
consumption of an alkaline solution on urine pH:
- higher (more basic)
vigorous exercise on urine volume:
-decrease urine volume (sweat a lot so body conserves water to maintain
vigorous exercise on the specific gravity of urine:
- increase
Why is there usually no glucose present in the urine? Why is there usually little or no protein present in the urine?
Why is there usually no glucose present in the urine?
-usually glucose is reabsorbed in the proximal convoluted tubule (active process) more than 99%
Why is there usually little or no protein present in the urine?
-proteins are too big to pass into bowman’s capsule during glomarular filtration so stay in blood
Define diuresis
- kidneys filter too much bodily fluid
* Increases urine production + bathroom frequency
endocrine glands
- (“ductless”) glands
* secretions called hormones
Hormones
- Chemical messengers secreted by cells into bloodstream.
- Regulate metabolic functions of other cells.
- The tissue specifically influenced by a particular hormone is termed the target tissue.
- Hormones effects not immediate, but are long lasting
Pituitary Gland
Controls/influences most of the other endocrine glands.
2 Lobes
Anterior Pituitary Gland
- Glandular
- 6 hormones (regulated by hypothalamus releasing factors)
Posterior Pituitary Gland
- Neural tissue
- 2 hormones (that are made by hypothalamus)
Thyroid Stimulating Hormone (TSH)
stimulates thyroid gland.
Adrenocorticotropic Hormone (ACTH)
stimulates cortex of adrenal glands
Follicle-stimulating Hormone (FSH)
controls growth and functioning of gonads.
Lutenizing Hormone (LH)
promotes production of gonadal hormones.
Growth Hormone (GH)
- promotes growth of all of the tissues in the body.
* works with glucagon to increase blood glucose levels.
Prolactin (PRL)
stimulates the milk production of the mammary glands in lactating females.
posterior pituitary gland
• does not manufacture any hormones of its own (not a “true” endocrine gland, only a storage area)
- Antidiuretic hormone (ADH)
- Oxytocin: stimulates smooth muscle contractions in uterus for delivery of a baby. Stimulates milk ejection from the mammary glands in lactating females.
Thyroxine
• Thyroid Hormone
- affects metabolism of all tissues in body by stimulating glucose oxidation
- increases metabolic rate, basal metabolic rate and body heat production.
Calcitonin
- Thyroid Hormone
* lower blood calcium levels by inhibiting bone break-down and promotes deposition of calcium in bones.
adrenal gland
- above kidney, flattened pyramid-shaped
* 2 distinct regions: outer cortex + inner medulla
adrenal cortex
-3 zones
- comprising 80-90% of the gland
- produces many hormones known as corticosteroids, all synthesized from cholesterol.
•zona glomerulosa:
-outer,
makes aldosterone (increase reabsorption of Na/water, increase blood volume/pressure)
- secrete mineralocorticoids which affect mineral (electrolyte) concentrations of the body fluids
• zona fasciculata:
- makes cortisol (fighting stress, increasing glucose metabolism, and preventing inflammation)
• zona reticularis:
-inner, makes weak androgens (can be converted to testosterone and estrogen)
adrenal medulla
- innermost part of gland.
- secrete epinephrine and norepinephrine in stressful situations and during exercise.
- fight/flight
pancreas
- mixed gland composed of both exocrine and endocrine tissue
- exocrine gland: produce digestive enzymes.
- endocrine tissue: tiny cell clusters (Islets of Langerhans) produce insultine + glucagon
Two major hormones are released from the Islets of Langerhans
Insulin
- lowers the blood glucose level, Beta (β) cells
- glucose –> muscle glycogen, liver glycogen, or fat
Glucagon
- raises the blood glucose level, Alpha (α) cells
- liver glycogen–> glucose
Diabetes mellitus
- insulin production is insufficient (Type I diabetes)
* insulin’s effectiveness on target tissues is reduced (Type 2 diabetes)
