Animal Anat -- Ion, Water, and Nitrogen Balance

Osmotic Regulation

Osmotic pressure of body fluids

Ionic Regulation

Concentrations of specific ions

Nitrogen Excretion

Excretion of end-products of protein metabolism

Ionoconformers 

Exert little control over ion profile within the extracellular space

Osmoconformers

Internal and external osmolarity are similar

Stenohaline

Can tolerate a narrow range of osmolarity

Euryhaline

Can tolerate a wide range of salinities

Eurohaline Osmoconformer

Will tolerate and accommodate a large change of osmolarity before death

Blue crab

Stenohaline Osmoconformer

Can’t tolerate much change in osmolarity before death

Lobster

Euryhaline Osmoregulator

Maintains constant state over a wide range of osmolarity

Intertidal bony fish

Stenohaline Osmoregulator

Can only maintain constant state over a small range before death

Deep ocean fish

Epithelial Tissue

Form boundary between an animal and their environment. Have physiological functions in respiration, digestion, and ion and water regulation

Stratum Corneum

Formed from keratinocytes turned into corneocytes that then further differentiate into cells packed with structural proteins.

Cells under apoptosis, but the skeletons remain forming the “cornified envelope”

Aquaporin Proteins

Increase water permeability by 100x

Mucus

Cornified stratum corneum with keratin

Transcellular Transport

Movement through the cell across the membranes

Paracellular Transport

Movement between cells

Electroneutral Cotransporters

Exchange anions for cations so no change in net charge differential

Electroneutral exchangers

glucose transporters

Positive PNA

Used for ion transport in fish

Used to bring in Ca

Negative PNA

Used for ion transport in fish

Used to bring in the Na

Diadromous

An animal that migrates between saltwater and freshwater

Catadromous

Live in freshwater, migrate to saltwater to spawn

eels

Anadromous

Live in saltwater, migrate to freshwater to spawn

Salmon

Salt Gland

Gland located near the eye, drain into ducts that empty near the nostril

Rectal Gland

accessory excretory organ in elasmobranchs, empties into digestive tract

Blood Urea Nitrogen

On serum chemistry panels, tells you about protein metabolism in the kidneys

Kidney

Internal organ most mammals have a form of, used to maintain ion and water balance

Nephron

The functional unit of the kidney

Renal Tubule

Lines with transport epithelium

various segments with specific transport functions

Glomerulus

A part of the vasculature of the kidneys

A ball of capillaries, surrounded by the Bowman’s Capsule

Filtration

Process of Urine Production

Filtrate of blood formed at glomerulus

Reabsorption

Process of Urine Production

Specific molecules in the filtrate removed

Secretion

Process of Urine Production

Specific molecules added to the filtrate

Excretion

Process of Urine Production

Urine is excreted from the body

Mesangial Cells

Cells used to monitor blood pressure and filtration within glomerulus

Primary Urine

Initial filtrate filtered in Bowman’s capsule that is isosmotic to blood

Renal Threshold

Concentration of a specific solute that will overwhelm the reabsorptive capacity

Proximal Tubule

Most of the solute and water reabsorption

Active secretion of materials not filtered 

Loop of Henle

A U-shaped structure in the kidney’s nephron that concentrates urine by creating an osmotic gradient.

Descending Limb

Part of the Loop of Henle

Water into the IF

Ascending Limb

Part of the Loop of Henle

Solute into the IF

Collecting Duct

Part of the Loop of Henle

Drains multiple nephrons, carries urine to renal pelvis, reabsorption of water

Parathyroid Hormones

Transport Hormone in the Distal Tubule

Increases Ca reabsorption

Aldosterone Hormones

Transport Hormone in the Distal Tubule

Increases K secretion

Diuretics

Stimulate excretion of water

Antidiuretics

reduce excretion of water

Glomerular Filtration Rate

Amount of filtrate produced per minute

Oncotic Pressure

Osmotic pressure due to protein concentration in blood

Vasopressin

Antidiuretic

Increases water reabsorption by increasing the number of aquaporins

Aldosterone

steroid

Control ion excretion

stimulates Na reabsorption from urine, enhances K excretion