Hormonal communication Flashcards
Communication systems
Nervous and hormonal systems, which together coordinate the activities within a whole organism.
Cell siganlling
Cells use to communicate with adjacent and distant cells: insulin released by beta cells in the pancreas is transported to liver cells and binds to receptors on their cell surface membranes to increase uptake of glucose from the blood.
Homeostasis
Maintenance of a constant internal environment via physiological control systems to ensure optimum conditions for enzymes to work: body temp, blood pH, blood glucose.
NEGATIVE feedback
Negative feedback
When there is a deviation from normal values, reverse/counteract the change to restore optimum levels.
Positive feedback
Deviation from set limit triggers response to increase the deviation further: during childbirth, baby’s head presses on cervix causing oxytocin to be released, causing uterus to contract and release more oxytocin.
Endotherm
Physiological responses to regulate internal body temperature via nervous responses.
Peripheral temperature receptors detect external temperature changes triggering vasodilation/vasoconstriction as well as sweating/shivering.
Ectotherm
Internal body temperature dependent on environmental temperature, adapting their behaviours to minimise temperature change to their bodies: basking in sun or moving to shade.
Liver structure
Hepatocytes
Receives oxygenated blood through hepatic artery and leaves via hepatic vein.
Kupffer cells
Macrophages in sinusoids of liver which engulf pathogens via phagocytosis.
Functions of Liver
- glycogen storage
- detoxification
- carbohydrate and protein metabolism
- amino acid synthesis
- bile production
Detoxification
Neutralisation and breakdown of unwanted chemicals (alcohol, drugs, toxins)
Deamination
Amine group removed from amino acid, converting it into ammonia which occurs in the liver as proteins cannot be stored.
Kidney structure
2 kidneys
Renal artery: supplies blood to be filtered
Renal vein: carries filtered blood away
Cortex, medulla, pelvis (composed of nephrons).
Nephron structure
Bowman’s capsule
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Collecting duct
Bowman’s capsule
Ultrafiltration: afferent arteriole is wide than efferent arteriole (80% water lost by ultrafiltration)
creates high hydrostatic pressure
Small molecules and water forced out of capillaries into renal capsule, and plasma proteins and blood cells remain in blood.
Proximal convoluted tubule
Selective reabsorption: walls made of microvilli epithelial cells which provide large SA for reabsorption of glucose into cells.
Osmoregulation
Process of controlling water potential of blood with hormones: antidiuretic hormone ADH released from pituitary gland.
Nephron
Blood filtered and useful substances are reabsorbed into the blood.