homeostasis and cells Flashcards
major systems maintaining health and optimal homeostasis
nervous and endocrine system
define homeostasis
homeostasis monitors the bodies environment for changes and signals mechanisms to prevent disturbance and maintain optimum conditions
what is the importance of maintaining consistency of the internal environemnts
failure to compensate for external changes can cause illness or disease
what is negative feedback
the original condition is removed/becomes switched off by the response
what is feedforward control
additional receptors are used to anticipate change and activate response before initial disturbance
how is water split in the body
2/3 ICL
1/3 ECL
barrier between plasma and interstitial fluid
blood vessel capillary wall which is permeable to everything but plasma protein and blood cells
barrier between interstitial fluid and intracellular fluid
cell membrane which has selective permeability
what is dilution principle
c=m/v
how could you find plasma fluid volume
evans blue or l125 radioactive albumin attach to plasma proteins
how would you find extracellular volume
requires something that freely crosses capillary walls but not cell membranes e.g inulin, Cl or Na
how would you find total body water
no barrier for water in the body so loading dose of deuterated water is used and volume is calculated by:
ISF= ECP-PV , ICF = TBW-ECF
what are the structures present in all cell types
- cytoplasm
- ribosome
- cell (plasma) membrane
role of the nucleus
contains DNA and are sites of rRNA synthesis and ribosomal assembly
role of the endoplasmic reticulum
RER (ribosomes attached, modifies proteins) or SER (no ribosomes, lipid and steroid hormone production)
role of golgi apparatus
packages up proteins in preparation for transport out of the cell
role of ribosome
site of protein synthesis
role of lysosome
bound vesicles containing enzymes, responsible for the digestion of biological materials
role of peroxisome
bound vesicles containing enzymes, responsible for degrading long chain fatty acids and foreign toxic molecules
role of mitochondria
site of oxidative phosphorylation
role of flagella
enables movement
role of cillium
move water relative to the cell in a regular movement of the cilia
describe the structure of the eukaryotic plasma membrane
phospholipid bilayer = double layer of lipid with attached phosphate groups
describe the function of the eukaryotic plasma membrane
selectively permeable via protein receptors