Exam 5

urinary system componets

kidneys, ureters, bladder, and urethra

urinary system functions

eliminates waste

maintains concentration of solutes in blood

regulates blood volume and pressure

location of kidney

posterior wall of abdomen

lateral to vertebral column

right typically lower than left

adrenal gland on top of each kidney

kidney is surrounded by 3 tissue layers

renal fascia, perirenal fat, renal capsule

renal fascia

outermost layer, anchor kidney to deep fascia

perirenal fat

external to renal capsule

renal capsule

fibrous layer covering outer kidney surface

hilum (anterior to posterior)

renal vein

renal artery

renal pelvis/ureter

renal artery

from abdominal aorta

segmental arteries

initial branches in renal sinuses

interlobar arteries

extend through columns between pyramid

arcuate arteries

run along border between cortex and medulla

cortical radiate arteries

extend out into cortex

afferent artioles

supply individual nephrons at glomerus

efferent arterioles

drain blood from glomerys and supply to capillaries

cortex (kidney)

superficial tissue layer within kidney; lighter in color

renal columns

strips of cortical tissue projecting inward and separating pyraminds

medulla

deep tissue layer within kidney; darker in color

pyramids (kidney)

medullary tissue; base toward cortex and apex toward hilum

renal sinuses

inner cavity between branches of renal artery, vein and calyces

drainage of urine

renal papilla

minor calyx

major calyx

renal pelvis

what are the mains structures of a nephron

basic functional unit of kidney filtration

microscope

over 1 million per kidney

what is the path filtrate takes through the urinary system

renal corpuscle

proximal convoluted tubule

nephron loop

descending limb

ascending limb

distal convoluted tubule

collecting tubule and duct

renal corpuscle

glomerulus + glomerular capsule (bowmans capsule)

glomerulus

network of specialized capillaries; site of blood filtration

glomerular filtrate

fluid and dissolved solutes filtered from blood into capsular space; filtrate contains metbolic wastes but also useful material

proximal convoluted tubule

first part of renal tubule

reabsorbs organic nutrients, proteins, and ions from filtrate

filtrate concentration increased by absorbing water

microvilli present to increase surface area for reabsorption

nephron loop

second part of renal tubule

travels through medulla

descending limb

reabsorb water

ascending limb

impermeable to water and function is reabsorption of ions

distal convoluted tubule

third part of renal tube and end of nephron

some reabsorption of ions, acids, and toxins continue by active transport

returns from medulla into cortex and passes by vascular pole of glomerulus

juxtaglomerular apparatus

cluster of cells that autoregulate blood properties and thereby glomerular filtration

macula densa

monitors ion concentration in blood stream, can dilate arterioles and/or signal for release of renin

justaglomerular cells

cells between arterioles that release renin and erythropoitin

renin

enzyme that regulates blood pressure

erythropoietin

hormone that regulates red blood cell projection, which affects blood volume and pressure

antidiuretic hormone (ADH)

controls permeability of collecting ducts to water and this the concentration of urine exiting the collecting system

collecting system

collecting tubules

collecting ducts

papillary duct

collecting tubules

continuation of distal convoluted tubule

collecting ducts

receives fluid from several connecting tubules

papillary duct

receives fluid from several collecting duct; drain into minor calyx

what are structures responsible for expelling urine from the body

ureters

ureteral orifice

urinary bladder

urethra

urethral sphincters

ureters

smooth muscle tubes, enabling peristaltic contraction to propel urine

extend inferiorly from renal pelvis of kidney to bladder

ureteral orifice

slit-like opening in posterior wall of bladder through which urethers empty; prevent backflow when bladder fills, contracts

urinary bladder

hollow muscular organ

anterior to rectum and posterior to pubic symphysis (in females located anterior to vagina and inferior to uterus)

ruge

trigone

neck of urinary bladder

detrusor muscle

ruge

folds of mucosa in inner lining of bladder; disappear as bladder stretches

trigone

triangular area whose vertices are ureteral orifices and entrance to urethra

neck of urinary bladder

region surrounding urethral opening

detrusor muscle

smooth muscle in walls of bladder; expels urine upon contraction

urethra

extends from neck of urinary bladder to exterior (external urethral orifice)

length is shorter in females than males

male urethra divided into three segments: prostatic, membranous, spongy

urethra prostatic

passing from bladder through center of prostate

urethra membranous

passing through muscular pelvic floor

urethra spongy

passing through penis to external urethral orifice

urethral sphincters

internal and external

internal urethral sphincter

smooth muscle, provides involluntary control at point where urine leaves bladder to enter urethra

external urethral sphincter

skeletal muscle, voluntary control via resting muscle tone and relaxation

describe the major functions of the endocrine system

release hormones into the blood

cells with receptors are target cells/target organs

hormones

chemical messengers that change metabolic activity of another cell

protein (peptide) hormones

formed from chains of amino acids (growth hormone)

biogenic amines (amino acid derivatives)

formed by altering the structure of a specific acid (thyroid hormone)

steroid hormones

type of lipid derived from cholesterol (estrogen, testosterone, cortisol)

nervous and endocrine system

work together to regulate homeostasis

both affect specific target cells using chemical messengers

nervous system

uses nerve impluses along axons to reach target

rapid response to stimulus

localized, specific effects (specific muscle contracts)

response lasts a short time (milliseconds)

endocrine system

uses hormones that are transported via blood to their targets

relatively slow response

widespread effects throughout body (testosterone affects facial hair, acne, muscle growth, sexual response)

response lasts longer (minutes, days, weeks)

negative feedback

hypothalamus detects low levels of hormones

hypothalamus tells pituitary gland to fix low levels

pituitary tells organ to produce hormone

organ produces hormone

now theres enough hormone in bloo

hypothalamus detects enough hormone in blood

positive feedback

initial stimuli to endocrine system

pituitary releases hormone

hormone affects target

presence of hormone acts as stimulate to release more hormone

back to beginning

hypothalamus

“control center” of endocrine system

regulated endocrine system in 3 ways: signals to anterior pituitary, signals to posterior pituitary, direct stimulation of adrenal gland

the pituitary gland

located in sell turcica of sphenoid bone

connected to hypothalamus by infunibulum

anterior pituitary

extensive vascular network

secretes even hormones in response to regulatory hormones secreted by the hypothalamus

posterior pituitary

secretes only two hormones

hypothalamus to anterior pituitary gland

hypothalamus secretes regulatory hormones

regulatory hormones stimulate anterior pituitary gland to secrete seven different hormones

seven hormones anterior pituitary secretes

thyroid stimulating hormone (TSH)

adrenocorticotropic (ACTH)

follicle stimulating hormone (FSH)

luteinizing hormone (LH)

prolactin (PRL)

growth hormone (GH)

melanocyte stimulating hormone (MSH)

hypothalamus to psoterior pituitary

neurons from hypothalamus stimulate cells in posterior pituitary

posterior pituitary releases

vasopressin and oxytocin

vasopressin

restricts water loss in kidney

ocytocin

involved in uterine contraction during birth, sexual response, milk ejection reflex

anatomy of thyroid gland

butterfly shaped

anterior to trachea

extensive blood supply

two lobes connected by isthmus

how does thyroid gland work

hypothalamus releases regulatory hormone to anterior pituitary

anterior pituitary releases thyroid stimulating hormone (TSH)

TSH stimulates thyroid gland to release T3 and T4 (thyroid hormones)

thyroid gland histology

thyroid follicles lined by follicular cells

parafollicular cells release calcitonin, which regulated calcium homeostatis

follicular cells secrete T3 and T4

influence metabolic rate and protein synthesis

widespread targets (gut and heart)

parathyroid gland

for small glands located on posterior aspect of thyroid gland

how does the parathyroid gland work

low blood calcium

stimulates chief cells in parathyroid glands to release parathyroid hormon

targets: increased osteoclasts activity, kidney retain calcium

suprenal gland

attached to superior aspect of kidneys

suprenal cortex

secretes 24 different corticosteroids divided into: mineralocorticoids and glucocorticoids

mineralocorticoids

influence electrolyte composition (aldosterone targets kidneys to fine tune electrolytes)

glucocorticoids

influence glucose metabolism (cortisol targets liver to convert glycogen to glucose)

how does the suprarenal gland work

hypothalamus releases RH to anterior pituitary

anterior pituitary releases adrenocorticotropic hormone (ACTH)

ACTH stimulates release of corticosteroids form adrenal gland

suprarenal medulla

cells suprarenal medulla resemble sympathetic ganglia:

innervated by preganglionic sympathetic fibers (axons)

secrete: epinephrine and norepinephrine

(effects are similar to sympathetic “activation” but lasts longer

how does the suprarenal medulla work

hypothalamus directly innervates suprarenal medulla with preganglionic sympathetics

adrenal medulla secretes epinephrine and norepinephrine to widespread targets

pancreas

mixed gland in abdominal cavity with:

exocrine parts that secrete digestive juice

endocrine parts that secrete hormones

alpha cells of pancreas produce glucagon

raises blood glucose

targets liver to initiate gluconeogenesis

beta cells produce insulin

decrease blood pressure

targets liver, skeletal muscle, adipose tissure to increase uptake of glucose by cells

how does pancreas work? (blood glucose too low)

stimulates pancreatic alpha cells to release glucagon

targets liver to begin process of glucomeogenesis

how does pancreas work? (blood glucose too high)

stimulates pancreatic beta cells to release insulin

targets liver, skeletal muscle, adipose tissue to increase glucose uptake

testis

interstitial cells of the testis produce androgens

androgens (testosterone)

have widespread effects (facial hair, sexual function, muscular developement)

how do testis work?

hypothalamus release RH to anterior pituitary

anterior pituitary releases: luteinizing hormone (LH) and follicle stimulating hormone (FSH)

Luteinizing hormone (LH)

stimulates production of androgens

follicle stimulating hormone (FSH)

stimulates development of sperm

ovary

follicle cells surround oocytes and produce estrogen

after ovulation, follicular cells form corpus luteum, which produce progesterone