Excretion Flashcards
Excretion
The removal of wastes of metabolism from the body
Homeostasis
Maintenance of a constant internal environment
Ectotherms
Organisms that gain or lose heat from their external environment
Endotherms
Generate there own heat through metabolic reactions
Two layers of skin
Epidermis and dermis
Layers In the epidermis
Cornfield layer , granular layer , malphigian layer
Epidermis (function)
Prevents loss of water and entry of pathogens
Dermis (function)
Protects internal organs
Produces melanin, protects skin from uv light
Sebum in the skin (function)
Kills bacteria
Vitamins in the skin (function)
Sunlight on skin produces vitamin d
Food store in the skin (function)
Adipose tissue stores food
Sense organ in the skin (function)
Contains receptors that detect touch and temperature
Excretion from the skin (function)
Excretes sweat - salt and water
Vasoconstriction
In cold conditions erector muscles contract and hairs stand up (piloerection) to create a layer of heat , blood vessels close , brain causes shivering to produce heat
Vasodilation
In warm conditions sweat is released and water evaporates to lower temperature , blood vessels in skin dilate
Urinary system
Two kidneys , two ureturs , bladder and urethra
Renal artery
Carries blood with waste into kidneys
Renal vein
Carries filtered blood out of kidney
Outer layer of a cross section kidney
Cortex
Inner layer of a cross section kidney
Medulla
Location of filtration in a kidney
Nephrons
Filtration in nephrons
Renal artery divides into afferent arterioles then into glomerulus
Glucose amino acids water and urea leave the glomerulus through pressure and from glomeralur filtration
the pressure is produced from the afferent arteriole being smaller than the efferent arteriole causing force to push blood out of pores
Reabsorbtion
To prevent loss of amino acids salt water and glucose at the proximal convoluted tubule they are reabsorbed back into the blood
Food and salt ions are taken back by active transport
Water moves back by osmosis
Urea some salts and water pass as urine instead into the kidney and bladder
The bladder
Stores urine 400mls
Made of smooth muscle and epithelium
Osmoregulation
The regulation of the amount of water in the body by the kidneys
Hypthalmus
Detects water concentration in blood
ADH
Anti - diuretic - hormone
Water balance by hypothalamus
Hypothalamus sends message to pituitary gland if there is too little water in blood then pituitary gland releases adh the adh then causes collecting ducts in kidney to be permeable to water releases more water
Secretion
The production and release of chemicals
Ph control
Potassium and hydrogen ions secrete by active transport
when becomes acidic hydrogen is secreted into urine
Therefore kidneys regulate ph of blood also
