Intro to cell biology Flashcards
What is an ion?
an atom or group of atoms that has lost or gained one or more electrons
Are ions charged?
ions either have a positive or negative charge
Define physiology
the normal functions and phenomena of living organisms
What do physiologists view organisms as?
machines
How many cells, approximately, is the human body composed of?
30 billion
What is fluid inside cells known as?
Intracellular fluid (ICF)
What is fluid outside cells known as?
Extra cellular fluid (ECF)
What are the intracellular fluid and extracellular fluid seperated by?
the plasma membrane
What are the 6 properties of living cells?
assimilate materials from the internal environment that surrounds them
excrete waste products into the internal environment
grow
reproduce
respond to changes in their surroundings internal environments or the environment external to the body
exhibit motility
What is the ‘internal environment’ with regards to a cell?
the environment that is internal to the body but external of the cell
What percentage of the human body is water?
60%
What can extracellular fluid also be referred to as?
the internal environment
What two subcategories can extracellular fluid be split into?
intravascular fluid and interstitial fluid
what is interstitial fluid?
fluid that surrounds and bathes cells
What is intravascular fluid also known as?
plasma
What does mmol/L stand for?
millimoles per litre
What are the three main ions used in the body?
Sodium, calcium, potassium
What is the concentration of sodium ions in the ICF and ECF?
10 mmol/L and 140 mmol/L
What is the concentration of potassium ions in the ICF and ECF?
120 mmol/L and 4 mmol/L
What is the concentration of calcium ions in the ICF and ECF?
0.0001 mmol/L and 1.25 mmol/L
What does a difference in concentration of sodium and calcium ions cause in the cell?
Influx of ions into the cell down an electrochemical gradient
what does a difference in concentration of potassium cause in the cell?
an efflux of potassium ions out of the ICF to the ECF
Why is movement of ions down electrochemical gradients so important?
vital to many processes in the human body
what does the movement of sodium and potassium ions affect?
nerve impulses and action potential
What does the movement of calcium into ICF cause?
contraction of cardiac and skeletal muscles
what can the internal environment also be known as?
Extracellular fluid (ECF)
What condition must be met for humans to survive in such a variety of different areas?
provided their internal environment remains the same
Give 5 important properties of the internal environment (ECF)
temperature, pH, osmolarity, oxygen level, glucose concentration
How are the properties of the internal environment regulated?
by homeostatic mechanisms
What does homeostasis mean?
staying the same or simular
What sort of feedback does a homeostatic mechanism use?
negative
What happens during negative feedback in a homeostatic mechanism?
receptors or sensors monitor the variable (eg body temp), this information is sent to the processor (integrating centre) and compared against a set point or target. If there is a significant difference between the set point and the measured variable (eg person is too hot) effector mechanisms attempt to restore controlled variable to set point.
What is a change in core body temperature detected by?
central thermoreceptors
Where are thermoreceptors located?
in the hypothalamus
What effector mechanisms can be used to cool core body temp?
sweating and cutaneous vasodilation
What effect should the cooling effector mechanisms have?
cooling body temperature to set point
What effector mechanisms can be used to raise body temperature?
shivering, cutaneous vasoconstriction and piloerection (goosebumps)
What do baroreceptors do?
monitor pressure
Where are baroreceptors used to monitor blood pressure located?
Carotid sinus and aortic arch
What is the set point for mean arterial blood pressure?
~93 mmHg
What effector mechanisms are used to alter blood pressure if it is outside the set point?
Adjustments to the volume of blood pumped out of the heart per minute (cardiac output) and the resistance of the peripheral circulation (total peripheral resistance)
What receptors monitor partial pressure of CO2 in the bloodstream?
chemoreceptors
where are chemoreceptors located?
Brainstem
What is the set point for partial pressure of CO2 in the blood stream?
38-42 mmHg
What is the set point for core body temperature in humans?
37.7 celcius
Where are ribosomes located in the cell?
On the rough endoplasmic reticulum
What are ribosomes formed of?
RNA and protein
What are ribosomes involved with?
Protein synthesis
What structure is endoplasmic reticulum joined to?
Nuclear envelope
What are the 2 forms of endoplasmic reticulum and what are their functions?
Rough: proteins are synthesised and modified. Smooth: lipid biosynthesis and drug betoxification
How is the nucleus joined to endoplasmic reticulum?
Nuclear envelope
What does the nucleus contain?
DNA
What happens in the nucleolus?
Site of most RNA synthesis
What are the 4 types of protein found on the plasma membrane?
Transporter, anchors, receptors, enzymes
What is the function of the Golgi apparatus?
Sorts proteins and ensures they are delivered to the right place
What are perioxisomes and lysosomes involved in?
Perioxisomes: oxidative enzymes, lysosomes: hydrolytic enzymes for degradation of protein
What is the function of mitochondria?
Fuel oxidation, O2 consumption, ATP generation
What type of filament is involved in cell movement?
Actin
What matrix helps cells to move forwards?
Extra cellular
What structures help with the direction of cell travel?
Microtubules
What are the only cells in the skin that are able to continuously divide?
Basal cells
What layer of the cells do the basal cells remain in?
Basal layer
