Chapter 1 - Homeostasis and Excretion Flashcards
integumentary system function
hair, skin, nails
- forms external body covering
- protects deeper tissue from injury
- helps regulate body temp
- location of cutaneous (related to skin) nerve receptors
skeletal system function
cartilages
- protects and supports body organs
- provide muscle attachment for movement
- sit of blood cell formation -> bone marrow
- stores minerals (in bone marrow)
muscular system function
- produces movement
- maintains posture
- produces heat
nervous system function
brain, sensory receptor, spinal cord, nerves
- fast-acting control system
- responds to internal and external change
- activates muscles and glands
endocrine system function
- secretes regulatory hormones for:
-> growth
-> reproduction
-> metabolism
e.g. testosterone, estrogen, progesterone
cardiovascular system function
heart, blood vessels
- transports materials in body via blood by heart (e.g. oxygen, carbon dioxide, nutrients, wastes)
lymphatic system function
thoracic duct, lymph nodes, lymphatic vessels
- returns plasma to blood vessels
- cleanses the blood -> contains lymphocytes; gets rid of cellular debris
- involved in immunity
what are lymph capillaries?
- fills interstitial spaces between cells
- carries tissue fluids
respiratory system function
nasal cavity, pharynx, larynx, trachea, bronchus, lungs
- keeps blood supplied with oxygen
- removes carbon dioxide
digestive system function
mouth, esophagus, stomach, small and large intestine, rectum, anus
- breaks down food
- allows for nutrient absorption into blood
urinary system function
kidney, ureter, bladder, urethra
- eliminates nitrogenous wastes - uric acid, ammonia
- maintains acid-base balance - maintains pH level in body
- regulates water and electrolytes
reproductive system function
woman: mammary glands (breast), uterine tube, ovary, uterus, vagina
man: seminal vesicles, prostate gland, penis, vas deferens, scrotum
- produces offspring
what is homeostasis?
the maintenance of static or constant conditions in the internal environment
what is homeostasis imbalance
a disturbance in homeostasis causing diseases (not all the time)
conditions for an organism to be in homeostasis
- optimal conc. of gases, nutrients, ions and water
- at optimal temperature
what is the control system made of?
- sensory receptors
- control centre
- effector
function of sensory receptors
thermoreceptors
- responds to stimulus
- sends information to control centre
function of control center
brain
- determines set point
- analyzes information
- determines appropriate response
function of effector
sweat glands
- receives information from control centre
- provides reponse
systems that maintain homeostasis
nervous and endocrine (hormonal)
what is negative feedback
a response that is negative/against original stimulus. it shuts off original stimulus, or reduces its intensity
what is vasoconstriction
contraction of blood vessels (become smaller), reduces warm blood flowing near surfaces
what is vasodilation
blood vessels dilate (become wider), allows more blood flow
what happens during heat stress
- thermoreceptors detect an increase of body temp
- hypothalamus signals to sweat glands and blood vessels
- sweating is initiated and vasodilation is carried out
- heat from the blood is lost to the skin so blood can return to core of the body and cool internal organs
what happens during cold stress
- thermoreceptors detect a fall in temperature
- hypothalamus receives signal and send signals to blood vessels, smooth muscles surrounding hair follicles and skeletal muscles
- vasoconstriction is carried out, hair “stands” trapping warm air and shivering is activated
- increase of metabolic rate to produce heat
- less heat is lost
function of insulin
- produced by beta cell of islets
- target organs: liver, skeletal muscles, adipose tissue (body fat)
- decrease blood glucose levels
- some extra glucose stored as glycogen
- the rest of the glucose is moved into cells for use in cellular respiration
function of glucagon
- produced by alpha cells of islets
- target organs: liver
- increase blood glucose level
glucagon allows glycogen to be broken down into glucose
what is diabetes
metabolic disorder characterized by hyperglycemia (high blood glucose) due to an absolute or relative lack or insulin or to a cellular resistance to insulin
difference between type 1 and 2 diabetes
type 1: insulin dependent; not able to produce insulin
type 2: insulin resistant
what is urea
- waste product made when liver breaks down proteins that the body doesnt need
- contains nitrogen
components of urinary system
- 2 kidneys (left and right)
- 2 ureters
- 1 urinary bladder
- 1 urethra
what is a nephron
functional unit of kidneys
components of a nephron
renal corpuscle, bowman’s capsule, glomerulus, proximal tubule, loop of Henle, distal tubule, collecting duct
what is the renal corpuscle
bowman’s capsule and glomerulus
what is bowman’s capsule
- enlarged end of nephron
- opens into proximal tubule
what is the glomerulus
a global cluster of capillaries
what is the proximal tubule
- where filtrate passes
filtrate: after waste is filtered, useful substances will be absorbed back, whatever left is urine
what is the loop of Henle
- contains descending and ascending loops
- water and solutes pass through thin walls by diffusion
what is the distal tubule
structure between loop of Henle and collecting ducts
what are the collecting ducts
- empties into calyces
- carry fluid from cortex through medulla
steps in urine formation
- ultrafiltration/glomerulus filtration
- reabsorption
- tubular secretion
what happens during ultrafiltration (urine formation)
- water and solutes (glucose, ions, etc) are filtered into the Bowman’s capsule to form the filtrate
what happens during reabsorption (urine formation)
- useful nutrients (glucose, amino acids, water, etc) are reabsorbed into peritubular capillaries
what happens during tubular secretion (urine formation)
substances not needed (hydrogen ions, drugs, etc) are secreted directly into tubules from the capillaries
what is ADH (antidiuretic hormone mechanism)
- ADH is released when conc. of solutes in plasma increases/blood pressure increases
- they act on kidneys, absorb more water (less urine volume)
- result: maintain blood volume and blood pressure
- diuresis: production of urine
how is ADH used/activated
- high blood osmotic pressure (water out of cell>water into cell) stimulates hypothalamic osmoreceptors
- osmoreceptors activate neurosecretory cells that synthesize and release ADH
- ADH is released into bloodstream (more water, less urine)
opposite:
- low blood osmotic pressure inhibits hypothalamic osmoreceptors
- reduction/stop of ADH secretion (less water, more urine)
what tissues does ADH target
- kidneys - retain more water, less urine output
- sweat glands - less water lost by perspiration from the skin
- arterioles - constrict, increasing blood pressure
