Homeostasis Flashcards
what must be removed from cells
waste and carbon dioxide
what must be supplied to cells
nutrients and oxygen
what is homeostasis
the various physiological arrangements that serve to restore the normal state once it has been disturbed
what are the different systems found within the body
- those that interact with the external environment and expend energy
- those that interact with the internal environment and achieve homeostasis
- those that control other systems
what are examples of body systems that control other systems within the body
nervous system and endocrine system
what are examples of systems that interact with the internal environment and achieve homeostasis
cardiovascular system, respiratory, excretory and alimentary system
what are examples of systems that interact with the external environment and expend energy
the nervous, locomotor, and reproductive systems
what does the enzyme pepsin do
works in the stomach and breaks down certain components
what does trypsin do
works in different areas of the body, working at a neutral pH
what are the different conditions for homeostasis
- temperature
- oxygen
- calcium concentrations
- bicarbonate
- carbon dioxide
- pH
- glucose
- blood pressure
what are the two systems that are part of the control of homeostasis
the feedback control and negative feedback control
what is the shape of a normal distribution curve
bell shape curve
describe the process the body goes through when core body temperatuere goes down
- body temperature decreases
- hypothalamus receives this
- muscle response to increase heat production such as less sweating
what is the circadium rhythm
the internal process that regulates the sleep cycle
what happens to our body temperature during meals
body temperature will increase
what is interstitial fluid
fluids between tissues
what are the two forms of cellular communication
electrical and chemical communication
how does electric transmission work
occurs via gap junction and involves direct contact between cells. the gap junctions allow the flow of a current from cell to cell, there is a rapid transmission in both directions.
what are examples of cells that use electrical transmission to communicate
cardiac muscle and some smooth muscle cells
what is a syncytium
linked cells that act together as one unit
what occurs in chemical transmission
from cell to cell there is a synapse where a chemical transmitter will diffuse across. this is a one way transmission and is most common in the nervous system
when does paracrine signalling occur
from one cell to several cells
when does endocrine signalling occur
from many cells to many cells
what is the sequence of events of chemical communication
- the impulse arrives at a terminal of a presynaptic cell
- transmitter is released from storage vesicles
- transmitter diffuses in synaptic cleft
- transmitter binds to receptor on postsynaptic cell
what is an excitatory response
this is when an impulse is generated, and the muscle contracts, and a gland secretes
what is an inhibitory response
the cell is switched off
what is paracrine communication
when one cell communicates with several cells locally. can be part of a cascade of reactions
which cells most often use paracrine communication
defence cells during inflammation
what is autocrine communication
this is where chemicals act on cells by releasing it
what occurs in endocrine transmission
chemicals are sent to all parts of the body via the bloodstream.
what cells will endocrine transmission work on
those with the correct membrane proteins that make them target cells
what are nerves and hormones both used for
communication
what is neural communication
communication that can either be specific or localised, and are suitable for rapid response. involves involuntary muscle contraction, a sensory system, a salivary gland, and blood pressure
how many cells does neural communication affect
many
what is hormonal communication
communication that leads to coordinated, body wide actions. it is slow to act but the effect persists
what are some examples of body responses related to hormonal communication
- gastrointestinal gland responses
- control of metabolism
- regulation of the menstrual cycle
what are first messengers
chemical transmitters acting on the receptor protein
can all first messengers enter the cell
no
what are steroid transmitters
lipids that pass through the outer cell membrane that act on receptors in the target cells. the steroid receptor complex acts on dna in the nucleus to initiate protein synthesis. the protein alters the cell function, and the hormones have a delayed function
what are peptide transmitters
these are transmitters that cant enter through the cell membrane. they instead bind to plasma membrane receptors and set up a series of reactions controlled by g proteins. then they activate second messenger systems like cyclic amp and calcium ions
how are g proteins activated
the transmitter binds to a membrane receptor and activates the g protein. the atp is converted to cyclic by enzyme adenyl cylase (adenylate cyclase)