B3 Flashcards
what are epithelial cells
they line any surface that is in contact with the external environment and line the surface of internal organs eg. the lungs
what are the two types of epithelial tissue that line the lungs?
squamous epithelium and columnar epithelium
explain what columnar epithelium cells are
cilliateed columnar epithelium cells line the upper airway (trachea and bronchi),
they have a lot of mitochondria
the cilia move mucus away from the lungs which prevent any inhaled particles causing infection.
what do goblet cells produce?
they produce / release sticky mucus onto the surface of the epithelium which acts as an lubricant
what does the mucus layer do?
it helps to trap any unwanted particles that are present in the air that you breathe
what are cilia
they are tiny hairs on the outer surface of epithelial cells, they waft back and fourth to move surface mucus out of lungs
squamous epithelium cells
they are very flat and thin with egg-shaped nuclei, often one cell thick
what is chronic obstructive pulmonary disease (COPD)
it includes multiple conditions and is more common in smokers as substances in smoke damages the lungs.
what does cigarette smoke cause?
it causes cilia columnar epithelium to slow and stop beating and eventually die so mucus builds up, which clogs the arteries and which causes more coughing that ruptures the thin alveolar epithelial cells and destroys them, this reduces the area for gas exchange and provides a good environment for pathogens to grow
why do ciliated columnar cells contain many mitochondria ?
they have cilia that move particles or mucus eg. in the lungs they move inhaled particles out of the lungs. in order to keep moving, the cilia need a lot of energy, which is provided by respiration, which occurs in the mitochondria
what are blood cells line with
epithelial tissue
what is meant by the term tissue
a group of similar or specialised cells carrying out a specific function
state the type of epithelial tissue found in both alveolar and endothelial tissue
squamous
when do blood clots form?
when there is damage to tissue, if there is a damage to an artery and a clot forms it can result in health-related problems.
what are blood vessels lined with?
endothelial tissue
what is endothelial tissue made up of
it is made up of a single layer of flat, long cells, which are orientated lengthways in the direction of blood flow. their function is to provide a smooth covering surfacec so blood can flow easily over them
arteries
Carry blood away from the heart to tissues of the body
They have thick muscular walls to carry blood at high speed
carry blood at high pressure
do not contain valves
veins
Carry blood from the tissues of the body into the heart
carry blood at lower pressure than the blood in arteries.
thinner walls than arteries
have valves to prevent backflow
capillaries
Capillaries have thin walls which allow them to effectively perform their function of allowing substances to easily and quickly diffuse or pass throuhg them.
they are much thinner than arteries and veins, as their walls are made up of only a single layer of endothelial cells, the flat cells that line all blood vessels.
are arteries made up of the same tissue?
yes but in different proportions
they both have an outer layer of connective and elastic tissue, but is thicker in veins to prevent collapse of the vessel.
their middle layer is made of smooth muscles, connective and elastic tissue, but is thicker in arteries to maintain bp.
the inner layer is mad of endothelial tissue
capillaries only have an endothelium
what is atherosclerosis
it is the disease process that leads to coronary heart disease and strokes
fatty deposits can either block an artery or increase its chance of being blocked by a blood clot.
how can endothelial tissue lining of artery become damaged?
smoking and high blood pressure
artieries become narrow and the loss of elasticity restricts blood flow whcih increases blood pressure
what does cigarette smoke contain?
it contains many toxic chemicals, which can lead to atherosclerosis, the thickness of the blood increases which causes fatty deposits to build up on the walls of arteries and increases the risk of clotting.
smoking also increases blood pressure and heart rate, which causes damage to the endothelium.
describe endothelial tissue and explain how it is adapted to its function
endothelial tissue is made up of a single layer of long, flat cells, oreintated lengthways to the direction of blood flow. as they are flat, the surface is smooth which allows blood to flow more easil.
the diffusion distance is small, so substances can diffuse easily in and out of blood vessels into the surrounding tissue.
what is muscle?
muscle is a soft tissue, which can contract to maintain a position in the body or produce a movement
what is muscle made up of?
it is made up of bundles of cells called muscle fibres which are made up of myofibrils.
myofibrils are made up of the protein myosin and thin fillament made of actin.
what is sarcomere?
it is repeated units of actin and myosin fillaments
what happens when muscle contracts?
the thin actin fillaments move between the thick myosin filaments, which shorten the length of the sarcomere and the overall length of the muscle
what are slow twitch muscle fibres
slow contractions for aerobic endurance contain many mitochondria which supply energy from aerobic respiration contain lots of capillaries does not fatigue easily large oxygen and glucose stores eg. long distance running
what are fast twitch muscle fibres
fast contractions for anaerobic activities few mitochondria as energy for contraction from anaerobic respiration doesnt require oxygen contains a few capillaries fatigues easily little stored oxygen and glucose eg. sprinters
state the type of muscle cells that are an advantage to marathon runners and explain why
slow twitch muscle fibres
they contract slowly over long periods of exercise and do not tire easily
energy is from aerobic respiration, so they have many capillaries to transport oxygen and glcose to the cells for respiration and mitochondria for respiration to take place
what are nerves made up of?
cells called neurones
what are skeletal muscles?
skeletal muscles contain a thick filament called myosin and a thin filament called actin, the myosin binds to actin creating a stripy appearance.
they are are voluntary, this means they are under our conscious control as we can send impulses from the brain to the muscle
what do neurones carry?
they carry messages in the form of electric signals from one part of the body to another. these messages are also known as nerve impulses
what can the nervous system be divided into?
the nervous system can be divided into the peripheral nervous system and central nervous system which is made up of the brain and spinal cord.
explain the structure of a neurone
cell body- contains the nucleus and is where all materials needed by the cell are made
axon - is adapted to conduct an electric impulse called an action potential
myelin sheath - electrically insulating layer
axon terminals
node of Ranvier - gaps in myelin sheath; they allow the electrical impulse to pick up speed.
schwann cell - produces the myelin sheath
dendrite - receives chemical signals from the axon terminal of other neurons
are most nerve cells myelinated?
yes, those that arent are small diameter nerves usually responsible for transmitting pain eg. aches and soreness rather than sharp pain. they also detect temperature changes.
explain differences between non-myelinated and myelinated nerve cells
non myelinated nerve cells myelinated nerve cells
- DON’T have a myelin sheath | * do
- are grey | * are white
- transmit impulses slower | * transmit impulses very fast
- DON’T have nodes of Ranvier | * do
what is the mammalian nervous system?
it is a complex biological organ, which enables many animals including humans to function in a coordinated fashion.
what is the mammalian nervous system made up of?
cells called neurones
describe the 3 most common type of neurone
sensory neurone: connects sensory receptors to the central nervous system
relay neurone: found in the central nervous system
motor neurone: communicates from central nervous system to effectors
describe sensory neurones
they connect sensory receptors to the central nervous system
describe relay neurones
they are found in the central nervous system
describe motor neurones
they communicate from central nervous system to effectors
what is meant by progressive?
increases over time
what is meant by ‘de’ before a word
removal of
Multiple Sclerosis (MS) is known as a 'progressive de-myelinating disease' that affects the nervous system. suggest what 'progressive de-myelinating' means and how MS affects the transmission of nervous impulses.
progressive de-myelination means that the myelin sheaths gradually break down.
when the myelin sheath brakes down, it causes the nerve signals / impulse to be transmitted more slowly which disrupts how the nervous system normally communicates.
what do neurones send?
electric impulses, which are generated by changes in the concentrations of ions inside and outside the nerve cell causing a potential difference, called an action potential, which transmits an electrical signal between nerve cells.
what is an action potential and when does it occur?
action potential occurs when a neuron sends information down an axon, away from the cell body.
when are action potentials triggered?
by the depolarisation of the nearby membrane changing the potential difference to the threshhold potential.
what do Electroencephalogram (EEG) record ?
they record the brains electrical activity
and the potential difference between two electrodes is recorded
describe how EEGs work
they are placed on the head at specific positions, different electrodes record activity from different areas of the brain.
each electrode has a number and letter which show where the electrode is placed.
what are EEGs used for?
to diagnose and investigate epilepsy
investigate problems such as sleep disorders, dementia, head injuries and encephalitis
sudden changes in electrical activity may show that normal brain activity is suddenly interrupted and changed.
what can EEGs show
general changes inn how normal electrical activity looks on an EEG may show that there is a problem with the brain
evaluate the use of EEGs
they only show that there is a problem in an area of brain activity and can give a clue about what might be wrong, but they do not give a conclusive diagnosis
describe what an EEG shows
records the electrical activity of the brain
explain two factors that can affect brain activity
age
whether a person is awake or in different stages of sleep
whether they have their eyes open or closed
what they are
what are synapses?
they are gas between nerve cells / neurones, action potentials cannot pass between nerve cells across the synapse, so transmitter substances are used
what is the presynaptic membrane
before the synapse / gap between neurones
it allows the release of chemicals (neurotransmitters) when impulsese are arriving to stimulate impulses in the cell after the gap / synapse ( postsynaptic cell)
what are neurotransmitters
chemicals which transmit messsages between neurones
what is the postsynaptic cell
bit after the gap
what is acetylocholine
it was the first neurotransmitter to be discovered and has multiple functions such as the stimulation of muscles, it is largely made in the brain
it is broken down in the synaptic cleft by acetylcholinesterase
botulism toxin paralyses respiratory muscles, causing suffocation and death.
a) state whether botulism toxin prevents or stimulate the release of acetycholine
b) explain the effect of botulism toxin
a) it prevents the release of acetycholine
b) acetycholine is a neuro transmittter, which allows nerve impulses to stimulate muscles. if its release is prevented by botulism toxin, this would mean the muscle would be paralysed.`
parkinson’s disease and depression have been shown to be associated with what?
inbalances of important chemicals
what are some symptoms of parkinsons disease?
muscle tremors - shaking
stiffness of muscles and slowness of movement
poor balance and walking problems
speech difficulties and breathing
parkinson’s disease
it is associated with the death of a group of dopamine-secreting neurons in the brain, which results in the reduction of dopamine levels in the brain
what is dopamine?
it is a neurotransmitter that is active in neurones in the frontal cortex, brain stem and spinal cord.
it is associated with the control of movement and emotional responses.
describe treatments for parkinson’s disease
most treatments aim to increase the concentration of dopamine in the brain.
dopamine CAN’T move into the brain from the blood stream, but the molecule called L-dopa which is used to make dopamine can, it can also be turned into dopamine to help control the symptoms.
what is serotonin?
it is a neurotransmitter linked to feelings of reward and pleasure.
a lack of serotonin is linked to clinical depression ( prolonged feelings of sadness, anxiety, hopelessness, loss of interest).
ecstasy (MDMA) works by preventing the reuptake of serotonin.
th effect is maintaining a high concentration of serotonin in the synapse, which brings about the mood changes in the users of the drug
what do drugs do to the nervous system?
drugs affect the nervous system by interfering with the normal functioning of a synapse, some:
- may affect the release of the neurotransmitter from the presynaptic membrane
- may affect the interaction between the neurotransmitter and the receptors on the postsynaptic membrane
- may block the receptors on the postsynaptic membranes and prevent the neurotransmitters binding
what is prozac?
it is an example of an seretonin selective reabsorption inhibitor (SSRI)
it can be given to patients to reduce depression
serotonin is not reabsosrbed because the SSRI bind to reuptake proteins, which means there’s a high level or serotonin.
the increased level of serotonin in the synapse continues to bind to receptors in postsynaptic membranes, which increases the feelings of reward and pleasure.
explain how ‘dopamine agonists’ that mimic dopamine might be a useful treatment for parkinson’s disease/
dopamine agonists mimic dopamine, they bind to dopamine receptors at synapses
they trigger action potentials
