Week 1 Introduction and Homeostasis ✅ Flashcards
What is homeostasis?
The state of a constant internal environment
What factors contribute to homeostasis?
Osmolarity, pH, O2 and temperature
What is the role of rough endoplasmic reticulum?
Process proteins
What is the role of soft endoplasmic reticulum?
Process lipids
What is the role of centrioles?
Cell division
What is the role of lysozomes?
Digestion
What is the role of golgi?
Packaging
What is the significance of hypertonic and hypotonic fluid with cells?
Fluid outside cells is hypertonic
Fluid inside cells is hypotonic
What is potassium involved in?
Cardiac contraction
Where are goblet cells located?
Intestines and lungs
What are the precursor of osteocytes?
Osteoblasts
What are blast cells?
Early cells
Why does a sperm cell have mitochondria in its head?
Movement
What is a totipotent cell?
Can form any cell
What is a pluripotent cell?
Can form >200 cell types
What is a multipotent cell?
A differentiated cell but can form multiple
What is a unipotent cell?
Can only form 1 cell type
What triggers DNA (genes) to make certain proteins?
Transcription factors/regulatory proteins
What are the features of a stem cell?
Self renew and differentiate into any cell
What does apoptosis mean?
Cell death
What is the role of cholesterol?
Regulate communication
Keep cell membranes fluid
What is endocytosis?
Engulf and bring into cell as a vesicle and recycle into cell membrane
What kinds of molecules can cross cell layers easily and what examples?
Non-polar molecules e.g. O2, CO2, vitamins
What is the purpose of trans-membrane protein channels?
To transport charged/polar molecules
Which part of the bilayer is hydrophilic and which is hydrophobic?
Hydrophilic (charged) head
Hydrophobic tail
(Tails are pointed together)
Are hormones and blood pressure under homeostatic control?
Yes
Is heart rate and body fat under homeostatic control?
No
Are blood gas levels under homeostatic control?
Yes
What are the features of negative feedback loop?
Stimulus → receptors → control centre → effectors
What does a baroreceptor measure?
Blood pressure
What does a chemoreceptor measure?
Blood gases
What does a thermoreceptor measure?
Temperature of the skin and organs
What does an osmoreceptor measure?
Osmolarity
What does a glucoreceptor measure?
Glucose
Give an example of a positive feedback situation
Childbirth - Oxytocin
What is the difference between positive and negative feedback?
Positive feedback moves the changes further away until it reaches an END POINT
When would the body temperature ‘set point’ be altered?
Fever
What effect does a high temperature have on the body?
Stimulate WBC production and activity
Why is the elderly and infants more susceptible to problems with heat?
The elderly’s hearts are not as efficient in helping to regulate temperature
Infants have a high surface area:volume so lose heat more easily
How do we get temperature ‘in’?
Radiant heat
Voluntary production of heat e.g. muscles
Involuntary production of heat e.g. shivering
How do we get temperature ‘out’?
Evaporation of sweat
Conduction, convection
Which part of the brain is involved in temperature regulation?
Hypothalamus
What is an ‘anticipatory’ response?
Sympathetic response e.g. white coat syndrome with BP, about to run a race - heart racing before even set off
What is sensitisation?
Where there is more than 1 stimulus e.g. O2 and CO2 both affecting
What is ‘feed forward’ and what is an example?
Similar to anticipation response but at a lower threshold
E.g. having a drink and stopping before osmoreceptors detect plasma osmolarity return
How does behaviour affect homeostasis?
Babies and infants may not be able to do certain tasks
The elderly may forget to do certain tasks
How does ‘accomodation’ affect homeostasis?
Changes cell sensitivity
How does ‘acclimation’ affect homeostasis?
Long term adaptations - artificial means (lab)
How does ‘acclimatisation’ affect homeostasis?
Long term adaptations - natural means
How does ‘genetic adaptation’ affect homeostasis?
‘Survival of fittest’
How does ‘inherited adaptation’ affect homeostasis?
Years of generations e.g. fat, cold environment
How does ‘acquired adaptation’ affect homeostasis?
1) Mins/hours - cold, pH etc
2) Days/weeks - sweat
