Urinary and Digestive Systems

Function of the Kidneys

Regulating water and solute concentrations, ion concentration in extracellular fluid, acid-base balance, excreting waste, producing renin and erythropoietin, vitamin D

Ureters

Transport of urine from kidneys to bladder

Urinary Bladder

Temporary storage for urine

Urethra

Transports urine out of body

Kidney Location

Between T12 and L5,Liver is crowding it

Renal Cortex

Outer region of the Kidney

Renal Medulla

Deeper than cortex, medullary pyramids

Medullary Pyramids

Papilla, Renal columns, Lobes

Renal Pelvis

Tubes connected to ureter, Minor and Major Calyces

Minor Calyx

Areas that collect urine draining from papillae

Major Calyx

Collect urine from minor calyx, empty urine into renal pelvis

Flow of Urine

Renal Pyramid, Minor calyx, Major Calyx, Renal Pelvis, Ureter

Nephron

Structural unit that forms urine, over a million per kidney, Renal Corpuscle and Tubule

Renal Corpuscle

Glomerulus and Glomerular Capsule/Bowman’s Capsule

Glomerulus

Tuft of Capillaries, allows for filtrate formation

Glomerular Capsule/Bowman’s Capsule

Structure surrounding Glomerulus, Parietal and Visceral Layers

Filtration Splits

Allow filtrate to pass into capsular space

Renal Tubule

Single layer of epithelial cells, Proximal Convoluted Tube, Nephron Loop, Distal Convoluted Tube

Proximal Convoluted Tube

Cells with dense microvilli, function is to reabsorb

Nephron Loop/Loop of Henle

Descending Limb and Ascending Limb

Distal Convoluted Tube

Cells with few microvilli, Function is to secrete

Collecting Ducts

Receive filtrate from nephrons to push into papillae, contain principle and intercalated cells

Principal Cells

Maintain water and sodium balance

Intercalated Cells

Maintain acid-base balance

Cortical Nephrons

Entirely in cortex and most nephrons

Juxtamedullary Nephrons

Long nephron loop deep into medulla, produce concentrated urine

Glomerulus Capillary Bed

Specialized for filtration, managed by arteriole, high pressure

Peritubular Capillary Bed

Porous for absorption, cling to renal tubules

Vasa Recta

Vessels parallel to long nephron loops, function in forming concentrated urine

Juxtaglomerular Complex

One for each nephron, regulate rate of filtrate formation

Macula Densa

Cells of ascending limb, sense content of filtrate

Granular Cells

Cells of arteriole, sense blood pressure, secrete renin

Extraglomerular Mesangial Cells

Located in between, connect gap junctions

Physiology of Kidney

180 liters of fluid into 1.5 liters of urine, urine produced from filtrate

Glomerular Filtration

Passive process, pressure forces fluid into filtration membrane into Bowman’s Capsule

Net Filtration Pressure

The sum of forces responsible for creating filtrate

Tubular Reabsorption

Reclaims most tubular contents and returns them to the blood; most reabsorption happens in PCT. All organic nutrients are reabsorbed. Water can be reabsorbed in the descending limb, and Solutes can be reabsorbed in the ascending limb. DCT is hormonally regulated

Antidiuretic Hormone

Increase water absorption when dehydrated

Aldosterone

Increase solute reabsorption when hydrated, regulates sodium and potassium

Tubular Secretion

Disposing substances, controlling pH

Regulating Concentration in the Body

Body needs 300 mOsm

Countercurrent Multiplier

Interaction filtrate in nephron loop, More solute out of ascending limb then more water out of desceding limb, and vice versa

Countercurrent Exchanger

Vasa Recta and Interstitial Fluid, ability to reabsorb water and solutes back into the blood

Invertebrate Kidneys

Bring in interstitial fluid, release waste into environment

Insect Kidneys

Malpighian tubule empties into hindgut, release waste through pores on the body

Mammalian Kidneys

Abundant water means short nephron loops, Little water means long nephron loops

Body Fluids

Intracellular and Extracellular Fluids

Osmolarity

Concentration of solutes to water

Hyperosmotic

Higher osmolarity of one solution than another

Hypoosmotic

Lower osmolarity of one solution than another

Nonelectrolytes

Don’t dissolve in water, mostly organic

Electrolytes

Ions in the water, conduct electricity

Conformers

Internal environment stays similar to external environment

Regulators

Internal environment stays within a narrow range, despite change in external environment

Electrolyte Balance

Salt balance

Renin-angiotensin-aldosterone Mechanism

Decrease in sodium causes release of renin, increasing angiotensin II, which stimulates production of aldosterone

Function of Digestive System

Take In Food, Break it down, Absorb molecules, Rid indigestible material

Digestible Energy

Gross energy that can be broken down

Metabolize Energy

Used to support life. Net Energy

Specific Dynamic Action

Metabolize energy lost during digestive processes. Source of thermal energy

Vitamin A

Name - Retinol

Function - Visual Pigment, Gene Regulation

Symptoms - Night Blindness, Epithelial Damage

Vitamin D

Name - Calciferol

Function - Calcium and Phosphate Absorption

Symptoms - Rickets

Vitamin E

Name - Tocopherol

Function - Antioxidant

Symptoms - Anemia

Vitamin K

Name - Menadione

Function - Blood Clotting

Symptoms - Hemophilia

Vitamin B1

Name - Thiamin

Function - Coenzyme: Thiamin Pyrophosphate

Symptoms - Beriberi

Vitamin B2

Name - Riboflavin

Function - Coenzyme: FAD, FMN

Symptoms - Various Skin Disorders

Vitamin B3

Name - Niacin

Function - Coenzyme: NAD, NADP

Symptoms - Pellagra

Vitamin B5

Name - Pantothenic Acid

Function - Coenzyme: Coenzyme A

Symptoms - Adrenal and Reproductive Dysfunction

Vitamin B6

Name - Pyridoxine

Function - Coenzyme: Pyridoxyl Phosphate

Symptoms - Peripheral Neuritis

Vitamin Biotin

Name - Biotin

Function - Coenzyme: Biotin

Symptoms - Hair Loss, Skin Problems

Vitamin Folic Acid

Name - Folic Acid

Function - Coenzyme: Tetrahydrofolate

Symptoms - Megaloblastic Anemia

Vitamin B12

Name - Cobalamin

Function - Coenzyme: Methylcobalamin

Symptoms - Pernicious Anemia

Vitamin C

Name - Ascorbic Acid

Function - Antioxidant, Connective Tissue Growth

Symptoms

Lipases

Release Fatty Acids from Triglycerides and Phospholipids

Proteases

Digest proteins

Amylases

Break down polysaccharides

Nucleases

Break down DNA into nucleotides

Enterosymbionts

Live within the lumen of GI tract

Exosymbionts

Actively cultivated outside the body

Endosymbionts

Embedded within or in between host cells

Phagocytosis Vesicles

Digestion occurs inside vesicles, Breakdown products released into the cell

Alimentary Canal

Muscular tube digests food, Mouth Esophagus Stomach Small Intestine Large Intestine Anus

Digestive Glands

Produce secretions that help break down food stuffs

Ingestion

Eating

Propulsion

Movement of food through the alimentary canal

Peristalsis

Alternative waves of contraction and relaxation to push food down

Mechanical Breakdown

Chewing, Mixing food with saliva, churning food in stomach

Digestion

Enzymatic break down of complex food molecules into chemical building blocks

Absorption

Passage of digested fragments from lumen of GI Tract into blood

Defecation

Elimination of indigestible substances via anus in form of feces

Salivary Glands

Produce saliva, begin breakdown of starch

Parotid

Salivary gland, anterior to the ear

Submandibular

Salivary gland, medial body of mandible

Sublingual

Salivary gland, Anterior to submandibular gland under tongue

Pharynx

Allows passage of food and air from mouth

Esophagus

Flat muscular tube that runs from pharynx to stomach

Heartburn

Stomach acid regurgitating into the esophagus

Stomach

Temporary storage tank that starts chemical breakdown of proteins

Chyme

Paste-like substance

Layers of Stomach

Mucosa, Submucosa, Muscularis Externa, Serosa