37 terms

Ch 32 Bio 191 UNR

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Homeostasis
used by organisms to maintain and internal balance regardless of external environment
Tissues
groups of cells with similar appearance and common function
Organs
different types of tissues organized into functional units
Organ systems
Groups of organs that work together
Epithelial tissues
Coverings and linings of the body and organs
apical surfaces face the lumen/outside
basal surfaces face underlying tissues
Connective tissues
Cells scattered through an extracellular matrix
ex. fibroblasts secrete matrix protein
Ligaments, tendons, fat, blood
Muscle tissues
Skeletal
Cardiac
Smooth
Skeletal muscle tissues
Voluntary, striated
Cardiac muscle tissue
Involuntary, striated
Smooth muscle tissue
Involuntary, unstriated
Nervous tissue
Neurons conduct nerve impulses
Glial cells support neuron functioning
Regulator
an animal that uses internal mechanisms to control the internal change despite external fluctuation
Conformer
and animal that allows its internal condition to change in accordance with external changes
Set point for homeostasis
A particular value for a variable that the body must stay at or close to.
ex. specific pH of blood=7.35
Stimulus
Fluctuations above or below the set point.
They are detected and trigger a response
Negative feedback
Control mechanism that reduces the stimulus
Endocrine system regulation
signaling molecules released can reach all locations in the body
Nervous system regulation
neurons transmit signals along dedicated routes, connecting specific locations in the body
Hormones
signaling molecules sent by endocrine system
can effect one location or whole body
receptor specific
Simple endocrine pathway
direct endocrine response to stimulus
The release of acidic contents into the duodenum stimulates endocrine cells there to secrete the hormone secretin This causes target cells in the pancreas to raise the pH in the duodenum
Neuroendocrine Pathways
they respond to external environment by relying on a sensor in the NS
Signals from the hypothalamus travel to a gland located at its base, called the pituitary gland The pituitary gland can be called the master gland because it releases so many different types of signaling molecules
Thyroid and parathyroid
Maintain metabolism and blood calcium level
Pancreas
Maintain blood sugar level
Adrenal glands
epinephrine secretion
Gonads (testes &ovaries)
reproductive hormones
Osmoregulation
the processes by which animals control the solute concentrations in the interstitial fluid and balance water gain and loss
Osmoconformers
Some marine animals are isoosmotic with their surroundings and do not regulate their osmolarity
Osmoregulators
Expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment
Osmolarity
the solute concentration of a solution determines the movement of water across a selectively permeable membrane
Adaptations for osmoregulations
Marine fish: Drink lots of water and excrete salt
Freshwater fish: Drink almost no water and replenish salt by eating or uptake across gills
Land animals: Body coverings that reduce water loss, drink water and eat moist foods, produce water metabolically
Urea
Vertebrates excrete urea, its less toxic but requires dilution
Uric acid
Most reptiles excrete uric acid as a paste, as it needs less dilution (little water loss)
energetically more expensive to produce
Key stages of most excretory systems
Filtration
Reabsorption
Secretion
Excretion
Vertebrate Excretory system
Blood carried to kidney by renal arteries & veins
Kidney has outer renal cortex, inner renal medulla
Nephrons in cortex alone or cortex & medulla
Nephrons are microscopic excretory tubules
Blood delivered by glomerulus (ball of capillaries)
Initial filtrate received by Bowman's capsule Urine passed to urinary bladder by ureters
Urine expelled from bladder by urethra
Nephrons
Microscopic excretory tubules in cortex alone or cortex and medulla of Kidney
Filtrate moves through the nephron
Proximal tubule
Loop of Henle (descending and ascending)
Distal tubule
Antidiuretic Hormone (ADH)
makes the collecting duct (of kidney) temporarily more permeable to water