Lecture 1 : Body Fluids and Urinary System Overview Flashcards by Brooke Routhier

Functions for survival

Maintaining Fluid, Electrolyte and Acid-Base Balance is critical for survival

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The human body is composed of ___ and _____ components

solid
liquid

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Body water composition

differs between men and women, and according to age and relative amount of body fat.

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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

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Tissues - water composition

Adipose tissue least hydrated (<20% water)
skeletal muscle (~75% water)

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___ and ___ make up most solid components of the body

Proteins
lipids

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Two main fluid compartments in the human body

Intracellular fluid (ICF)
Extracellular fluid (ECF)

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Intracellular fluid (ICF)

compartment (approx. 2/3)

all the fluid within the body’s cells

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Extracellular fluid (ECF)

compartment (approx. 1/3)

Plasma – liquid part of blood

Interstitial fluid (IF) – in spaces between cells

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Other fluids considered part of ECF:

Lymph
cerebrospinal fluid (CSF)
synovial fluid
aqueous and vitreous humors

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Water serves as the ______ in which different solutes are dissolved.

universal solvent

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All Body fluids consist of _____ and solutes

water (solvent)

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Solutes are ______ or ______

electrolytes
nonelectrolytes

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Electrolytes

dissociate into ions in water.
Ions are charged so can conduct electricity

(salts, acids, bases, some proteins)

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Nonelectrolytes

usually formed by covalent bonds, so don’t dissociate

Compounds are not charged

(glucose, lipids, urea, creatinine)

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water moves according to osmotic gradients

All dissolved solutes (particles) contribute to osmotic activity of a fluid:

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_____ have greater osmotic power

electrolytes

they dissociate into multiple particles while nonelectrolytes contribute only one particle.

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Electrolyte concentrations in the body are expressed as ________which takes into consideration charge of each ion

milliequivalents per liter (mEq/L)

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Electrolytes are unevenly distributed between _____, ____ and ______

plasma
interstitial fluid
intracellular fluid

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Na+, and Cl- high in ____

K+ and protein anions high in ____
Activity of _____ pumps keep Na+ and K+ separate

ECF
ICF
Na-K ATPase

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Weak bases part of buffering system

Bicarbonate
Hydrogen phosphate

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Fluid movement between compartments is constant and depends on _____ and _____ pressures

osmotic
hydrostatic

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Hydrostatic pressure

pressure of fluid in a system (like a capillary)

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Osmotic pressure

measure of the tendency of a solvent to move into a more concentrated solution

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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