Lecture 1 : Body Fluids and Urinary System Overview Flashcards
Functions for survival
Maintaining Fluid, Electrolyte and Acid-Base Balance is critical for survival
The human body is composed of ___ and _____ components
solid
liquid
Body water composition
differs between men and women, and according to age and relative amount of body fat.
Body water composition of:
Infants -
Healthy young men -
Healthy young women -
Elderly -
Infants ~73% water
Healthy young men ~60% water
Healthy young women ~50% water
Elderly ~45% water
Tissues - water composition
Adipose tissue least hydrated (<20% water)
skeletal muscle (~75% water)
___ and ___ make up most solid components of the body
Proteins
lipids
Two main fluid compartments in the human body
Intracellular fluid (ICF)
Extracellular fluid (ECF)
Intracellular fluid (ICF)
compartment (approx. 2/3)
all the fluid within the body’s cells
Extracellular fluid (ECF)
compartment (approx. 1/3)
Plasma – liquid part of blood
Interstitial fluid (IF) – in spaces between cells
Other fluids considered part of ECF:
Lymph
cerebrospinal fluid (CSF)
synovial fluid
aqueous and vitreous humors
Water serves as the ______ in which different solutes are dissolved.
universal solvent
All Body fluids consist of _____ and solutes
water (solvent)
Solutes are ______ or ______
electrolytes
nonelectrolytes
Electrolytes
dissociate into ions in water.
Ions are charged so can conduct electricity
(salts, acids, bases, some proteins)
Nonelectrolytes
usually formed by covalent bonds, so don’t dissociate
Compounds are not charged
(glucose, lipids, urea, creatinine)
water moves according to osmotic gradients
All dissolved solutes (particles) contribute to osmotic activity of a fluid:
_____ have greater osmotic power
electrolytes
they dissociate into multiple particles while nonelectrolytes contribute only one particle.
Electrolyte concentrations in the body are expressed as ________which takes into consideration charge of each ion
milliequivalents per liter (mEq/L)
Electrolytes are unevenly distributed between _____, ____ and ______
plasma
interstitial fluid
intracellular fluid
Na+, and Cl- high in ____
K+ and protein anions high in ____
Activity of _____ pumps keep Na+ and K+ separate
ECF
ICF
Na-K ATPase
Weak bases part of buffering system
Bicarbonate
Hydrogen phosphate
Fluid movement between compartments is constant and depends on _____ and _____ pressures
osmotic
hydrostatic
Hydrostatic pressure
pressure of fluid in a system (like a capillary)
Osmotic pressure
measure of the tendency of a solvent to move into a more concentrated solution
Water moves according to osmotic gradients:
from an area of lesser osmolality to an area of greater osmolalit
Solute distributions vary in different compartments because of
size, charge or transport proteins.
Anything that changes solute concentration in a compartment leads to water movement:
Water follows solutes! Almost always!
Osmosis occurs in most cells because they have an abundance of _____ in their plasma membrane
aquaporins
_____ generally moves freely between compartments, however ____often depend on transport proteins
Water (solvent)
solutes (ions, glucose, etc.)
Exchange between plasma and IF occurs across _____
capillaries (balance of hydrostatic pressure and osmotic pressure)
Exchange between IF and ICF occurs across ______
cell membranes – depends on membrane permeability (channels) and transporters
Because water moves freely between compartments: the osmolality of all body fluids _____
is equal
ECF solute concentration determines _____
ICF volume
If NaCl in ECF high, water ____ cells.
leaves
If ECF osmolality low, water ____ cells.
enters
Healthy people maintain osmolality of body fluids within narrow range ____
(280-300 mOsm)
Water balance is maintained by:
1)Thirst mechanism
2)Blood volume/pressure
3)Antidiuretic hormone
4)Electrolyte balance
5)Renin-angiotensin-aldosterone mechanism
6)Atrial natriuretic peptide
Dehydration leads to :
↑ osmolality in ECF, dry mouth:
Stimulates thirst and activates hormonal systems working at the kidney to conserve water
Overhydration leads to:
decreases inputs to thirst center
____ is most abundant cation in ECF
Sodium
Regulation of Sodium Balance
Only cation exerting significant osmotic pressure
Controls ECF volume and water distribution because water follows salt
Changes in Na+ levels affect :
affect plasma volume, blood pressure, and ICF and IF volumes
_____ is a major strategy in control of blood pressure
Regulating dietary sodium intake
Blood and tissue pH is maintained over a very small range:
Normal arterial pH 7.35-7.45
Hydrogen ion =
H+ = proton
each digit jump in pH represents :
10-fold change in hydrogen ion concentration
Kidneys regulate _____ and the ______
total volume of water in the body
total concentration of solutes (osmolality)
kidneys regulate the concentration of _____
ions in the extracellular fluids
kidneys regulate long term ____
acid-base balance
kidneys excrete _____ and _____
metabolic wastes
foreign substances (drugs, toxins)
Urinary
Organ system responsible for water, electrolyte, and acid-base balance, removal of nitrogenous wastes, urine production and excretion
Renal
of or related to the kidneys
Nephro-
of or related to the kidneys
Kidneys
Bean-shaped, convex lateral surface and concave medial surface
filter blood and form urine
Ureters
long muscular tubes that transport urine from kidneys to urinary bladder
Urinary bladder
muscular organ that stores urine
Urethra
tube that transmits urine from bladder to exterior
Renal hilum
at medial edge, is ‘connection’ point for the ureters, renal artery and renal vein, lymphatics, and nerves
The Urinary System Organs
Kidneys
Ureters
Urinary Bladder
Urethra
Renal hilum
The Kidneys lie on ___ abdominal wall
posterior
The Kidneys are retroperitoneal in the superior lumbar region, surrounded by three (3) layers of supportive tissue:
Renal fascia (outermost)
Perirenal fat capsule
Fibrous capsule
Fibrous capsule
thin layer of dense regular connective tissue surrounding kidney
Renal fascia
outer dense fibrous connective tissue anchoring the kidney to surrounding structures
Perirenal fat capsule
fatty mass that protects kidney
The internal structure of the kidney :
Outer cortex and Inner Medulla
Renal Cortex
superficial layer with granular appearance
Renal Medulla
Medullary (renal) pyramids
Renal Columns
Lobes
Medullary (renal) pyramids
cone-shaped tissue that appear striped due to parallel bundles of urine collecting tubes and capillaries
Renal Columns
inward extensions of cortex separating pyramids
Lobes
pyramid surrounded by cortical tissue
The kidneys have a rich ___ supply
blood
receive one-fourth of total cardiac output (about 1200 ml/min)
Renal artery
branch of abdominal aorta: branches to every lobe
Branches into cortex send an ______ to each nephron
Afferent Arteriole
Venous blood collected into ____ and sent to inferior vena cava
renal vein
The _____ is the basic structural and functional unit of the kidney
nephron
The Nephron consists of 2 parts:
RENAL CORPUSCLE
RENAL TUBULE
RENAL CORPUSCLE
responsible for filtering the blood and forming a “pre-urine”
RENAL TUBULE
adjusts contents of pre-urine to form urine
long length increases processing capability
removes 99% of water from pre-urine and returns it to the blood
RENAL TUBULE - basic functions
concentrates urine
adjusts ion levels
adjusts pH
Multiple nephrons empty into one_____ and each renal pyramid will have many collecting ducts.
collecting duct
____ funnel final urine from collecting ducts
toward renal pelvis
Calyces
Urine drains continuously from papilla of renal pyramids and empties into a _____
minor calyx
Several minor calyces drain into a _____
major calyx
3-5 major calyces drain into the ______
renal pelvis
Urine leaves the kidney at the point where the renal pelvis becomes the _____
ureter
Kidneys form urine continuously – collected by renal pelvis which drains into ____
ureter
Ureters deliver urine to _____
urinary bladder
_____ stores urine until time for urination
Urinary bladder
During urination, urine leaves bladder through ____ and out of body
urethra
