Unit 1 - Introduction Flashcards
What is physiology?
study of structure and function of a living organism and its components
State the level of organisation of living organisms
- chemical: atoms and mols
- cellular: neuron, lymphocytes
- tissue: collection of cells (e.g. connective tissue)
- organ: collection of tissues (e.g. heart)
- organ system: group of organs
- organism: individual form of life
How are cells held together?
Cell junctions
Name the different types of cell junctions:
- anchoring junctions
- gap junctions
- tight junctions
Name the primary tissue types found in the human body
- epithelial
- connective
- muscle
- neural
What is the function of the epithelia?
to protect the internal environment of an individual
What is the overarching function of epithelium tissue?
to regulate movement of materials between the internal and external environment, everything has to cross an epithelium
List the types of epithelia and their functions:
- exchange: rapid exchange of material
- ciliated: line airways and female reproductive tract
- secretory: synthesize and release products into the external environment/blood
- transporting: selective transport of material
- protective: found on surface of the body
Name the function of the connective tissue
to provide for structural support and barriers
The connective tissue has extensive extracellular matric (ECM). What does the ECM contain?
- proteoglycans
- collagen
- elastin
- fibronectin
Name the types of connective tissues and their functions:
- loose: elastic tissue (e.g. skin tissue)
- dense: strength (e.g. tendons)
- adipose: contains adipocytes (e.g. white and brown fat)
- blood: watery matrix lacking insoluble protein fibers
- supporting: dense substances (e.g. cartilage, bones)
What is the function of muscles?
contraction to produce force and movement
Name the types of muscles:
- skeletal: gross body movement
- smooth: influence movement of substances into/out of/within the body
- cardiac: only in heart, contraction to move blood
What is the function of neural tissue?
to carry info from one part of the body to another
Name the types of cells in neural tissue and their functions:
- glial cells: supporting cells for neurons
- neurons: carry info as electrical or chemical signals
Define “function” and “mechanism” as interrelated concepts in physiology:
- function refers to why a system exists, while mechanism refers to how a system works
- we study the mechanism to understand the function
What is homeostasis?
maintenance of a stable internal environment
Homeostatic control is oscillation around a set-point. How can the set-point change with time?
- acclimatization: e.g. acclimatization to altitude
environmentally induced change in physiological function w/o genetic change - circadian rhythms: daily biological rhythms
e. g. sleep-wake cycles, hormonal cycles
Name the 4 basic mechanisms of cell-to-cell communication:
- gap junctions
- contact dependent signals
- local communication
- long distance communication
What are gap junctions also known as?
direct cell to cell communication
Where are gap junctions found?
heart, lungs, liver, neurons
How does communication happen in gap junctions?
- via protein channels (connexons) between adjacent cells
TRUE OR FALSE:
Gap junctions are capable of opening and closing
TRUE
What is contact dependent signalling?
- interaction between membrane mols on 2 cells (e.g. surface mol of C1 binds to receptor protein in C2)
Where can contact dependent signalling be found?
- immune system
- during development: neural cells send out long extensions that must grow from central axis to distal ends of developing limbs
What is local communication?
- communication with neighbouring cells
- via autocrine and paracrine signals
- autocrine: chemicals that act on the cell that produced them
- paracrine: chemicals secreted that acts on neighbouring cells
Give an example of a paracrine signalling molecule
histamine: vasodilator
What engages in long distance communication?
- nervous and endocrine system
How is nervous system different from endocrine system in communication?
nervous system: use both electrical and chemical signals (e.g. neurohormones, neurotransmitters)
endocrine system: use only chemical signals: hormones
what are the 3 main domains of membrane spanning regions?
- extracellular: involved in binding the ligand
- transmembrane: hydrophobic
- intracellular: activates cellular response to ligand binding
TRUE OR FALSE:
Any molecule that can bind to a receptor and induce activity will elicit the response of the receptor
TRUE
membrane proteins act as ____
transducers
Name and define the 2 types of homeostatic control:
- local control: effects are exerted on neighbouring cells
e. g. paracrine control of blood vessel diameter in response to low O2 - reflex control: reaction in one or more organs controlled from elsewhere in the body
e. g. can be any of the long distance paths of the nervous and/or endocrine systems
What are the different types of feedback/control systems to regulate response loops?
negative feedback
- opposes or removes the signal, thus returning the variable to its original value
- homeostatic
- keeps the system near or at set-point
- e.g. blood pressure
Positive feedback
- reinforces stimulus, sends variable further away from set point
- needs external factor to turn off response
- not homeostatic
- e.g. labour
Feedforward control
- anticipatory control
- predicts change is about to happen, starts response loop, prevents change
e. g. sight or smell of food
