LC Biology- Excretion

Excretion

Process by which metabolic wastes are eliminated from the body

Stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move (gas exchange)

Lenticles

opening in bark of woody stem, allows gas exchange in stem to during respiration.

Ectotherm

an animal whose body temperature varies with the temperature of its surroundings

Endotherm

An animal whose body temperature is regulated by the internal heat the animal produces.

Epidermis

Outermost layer of the skin designed to provide protection.

Malpighian Layer

The layer of epidermis containing melanin pigment for colour and uv-protection. Cells constantly dividing by mitosis.

Granular Layer

Layer above malpighian layer in epidermis contains lots of waterproof keratin protein.

Cornified Layer

Outer layer of epithelium, dead cells constantly shedding.

Dermis

Middle layer of skin, contains connective tissue, sweat glands, hair follicles, sebaceous glands, blood vessels, nerve cells and collagen protein.

Subcutaneous Layer

Innermost layer of the skin, containing fat/adipose tissue

Functions of skin

Protective barrier from wear, infection, uv-light, temperature regulation, excretion, sense organ, Vit D production.

Piloerection

Contraction of erector muscles in skin follicles causing hair to raise and make goose-bumps, traps a layer of air to insulate body.

Vasoconstriction

Narrowing of blood vessels. Reduces blood flow and heat transfer by decreasing the diameter of superficial blood vessels. Keeps body warm.

Kidney

Filters waste from the blood like urea, water, salt and proteins.

Filtration

Occurs in Cortex of kidney where small substances are removed from the blood and put into the kidney.

Reabsorption

process in the kidney that puts useful substances (water, glucose, amino acids) back into the blood.

Cortex

Outer layer of the kidney where filtration occurs.

Medulla

Inner region of kidney where re-absorption occurs.

Ureter

A duct leading from the kidney to the bladder.

Bladder

a sac in which urine is stored/collected for excretion.

Urethra

tube leading from the bladder to the outside of the body for excretion of urine.

Urine

A watery fluid produced by the kidneys that contains urea and other wastes.

Sphincter Muscle

Muscle which controls bladder opening.

Nephron

Functional unit of the kidney

renal artery

blood vessel that carries blood to the kidney, C.

Renal vein

D blood vessel that carries blood away from the kidney and toward the heart

Efferent Arteriole

The small artery that carries blood away from the capillaries of the glomerulus.

Afferent Arteriole

The small artery that carries blood toward the capillaries of the glomerulus.

Glomerulus

The ball of capillaries at the beginning of the nephron where blood filtration takes place.

Bowman's Capsule

cup-shaped structure in the upper end of a nephron that encases the glomerulus

Proximal Convoluted Tubule

The portion of a renal tubule that collects the filtrate from Bowman's capsule.

Where selective reabsorption occurs

Loop of Henle

Section of renal tubule that descends into medulla. Here water reabsorption occurs and this conserves water and minimizes the volume of urine.

Distal Convoluted Tubule

The portion of a renal tubule that empties into the collecting tubule.

Final site of selective reabsorption

collecting duct

A segment of the nephron that returns water form the filtrate to the bloodstream.

Ultrafiltration

The process by which fluid and small molecules are filtered out of the blood in the glomerulus under high pressure.

Active Transport

Movement of particles from low to high concentration across the membrane that requires energy (ATP).

Secretion

Adding nonessential solutes and wastes from the body fluids to the filtrate, example potassium ions, hydrogen ions and ammonium ions

Glomerular Filtrate

The fluid that passes from the blood into the nephron and from which urine is formed.

ADH

Antidiuretic hormone (Vasopressin) made in pituitary of brain. It controls water absorption in the Collecting ducts of the Kidney. It promotes retention of water but is inhibited by alcohol.

Pituitary

Master endocrine gland, makes hormones to control other parts of the body