Sensory systems Flashcards
What are stimuli that we are sensitive to?
Mechanical Chemical Photic Thermal Pain Kinesthia
What are most of the sense organs sensitive to ?
external stimuli
What are the 6 different receptors?
Mechanoreceptors Chemoreceptors photoreceptors thermoreceptors nociceptors proprioceptors
What are mechanoreceptors sensitive to?
touch
hearing
balance and acceleration (vestibular system)
What are the chemoreceptors sensitive to?
taste (gustation)
smell (olfaction)
What are the photoreceptors sensitive to?
vision (photoreception)
What are the thermoreceptors sensitive to?
hot/cold
What are the nocieptors sensitive to?
various things (chemical, mechanical etc)
What are the proprioceptors sensitive to?
various (muscle spindles etc)
How can we sense blood pressure?
in our arteries, we have stretch receptors/mechanoreceptors which are sensitive to the diameter of our arteries
How do we detect blood oxygen/respiration?
respiration is controlled by the levels of oxygen and carbon dioxide
Chemoreceptors are sensitive to oxygen abd co2
What are some mechanoreceptors which can sense bp?
baroreceptors
What are other receptors sensitive to?
glucose etc
What are the sensory receptors for internal stimuli?
Mechanoreceptors- e.g baroreceptos
chemoreceptors
What animals have greater stimuli/senses than humans?
Aquatic animals
Sharks
How do aquatic animals such as fish have a greater number of stimuli?
They have lateral lines which is a sense organ which senses water movement which humans dont have
What are the receptors for lateral lines?
mechanoreceptors
How are animals considered to have even greater stimuli/senses to humans?
due to the earths magentic field which is percieved by animals such as birds and fish and is used for navigation (magnetoreception)
How do sharks and duck billed platypus have greater number of stimuli?
They can sense electricity, as they can sense action potentials and the electricity given off by the heart of other animals which are trying to hide for e.g.
So they can detect fish buried in the sea bed by detecting their electric fields (electroreception)
What other sense can be compared between animals and humans?
vision - (a sense)
What can fish birds and insects see?
can see UV light - see shorter wavelengths
What can snakes and beetles sensitive to?
Infrared
What is transduction?
Take the sensory stimulus and convert it to neurobiological activity
Layout the simple sensory system?
Neuron
stimulus- causes a change in membrane permeability leading to receptor potential e.g open Na channels - causing small depolarisation-
action potential which is carried to
CNS
What is a simple sensory system?
Smell
What is the sensory system of smell?
- Sensory neurone stimulated directly by the odour molecule
- an odour/olfactory molecule (chemical) dissolves in the nasal mucus
- sensory cells (bipolar neurones) which have cilia (increasing s.a)
- On the cilia, you have protein receptors
- the molecule binds to the protein receptors on the cilia
- Opens ion channels (which go into the bipolar)
- Action potential produced in the receptor
- CNS
What is the first cranial nerve ?
which takes the info from the nose to the brain
What is different about olfactory neurons compared to others?
they regenerate as they are replaced by epithelial cells which turn into sensory neurons
How are most sense organs built?
there is a specialised receptor cell that does not generate an action potential BUT it synapses with a sensory neuron that does
What cells are the taste buds made of?
made of 60 cells
sensory cells
epithelial cells
sensory neuron on the base of receptor cell
What is a specialised receptor cell for taste buds?
gustatory receptor
What is a receptor potential
when a receptor cell produces a small depolarisation which triggers an action potential in the sensory neuron
What do most senses involve?
a specialised receptor cell.
What is the receptor cell associated with?
an accessory structure
What is an accessory structure?
something which modifies the stimulus before it hits receptor cell e.g a membrane (hearing) or hair
What are the receptors which are most likely associated with the accessory structure?
tactile receptors
How are sensory neurons associated with accessory structures?
all sensory neurons are associated with the different accessory structure
e.g root hair plexus- wrapped around the base of the hair is a sensory neurone, so what activates the sensory neurone is the movement of hair so this is the accessory structure which makes this neuron sensitive to touch
the Pacinian corpuscle has a sensory neurone wrapped around with layers of connective tissue, which that accessory structure which makes it sensitive to deep pressure
What are the receptors involved in touch?
detect movement of hair thermoreceptors low-frequency vibration deep pressure light touch
What do accessory structures do?
Determines what cell is sensitive to.
touch is a good example of that
What hearing involves?
turning sound into electrical activity in the ear which the brain can interpret (transduction)
What is sound?
the variations in air pressure
What is pure sound?
tuning fork
What is middle c?
256Hz
What are sounds made of?
combination of notes forming more complex sound known as the quality of the sound.
How is middle c produced and what does it cause?
a tuning fork which produces middle c vibrates 256 times a second and is producing area of low and high pressure 256 times a minutes
How are high and low notes produced?
higher notes produce by more frequent vibration
lower notes produced by less frequent vibration
What does the pinna of the outer ear do?
serves to channel sound into the external auditory meatus
What happens when sound hits tympanic membrane?
when waves of air pressure come in external auditory meatus it is going to hit the tympanic membrane causing it to vibrate
What is the area of the tympanic membrane?
areas of 65mm
What happens when there is high and low pressure in the tympanic membrane?
area of high pressure the tympanic membrane moves in and low-pressure tympanic membrane moves out.-
What happens to these vibrations?
the movement is transferred through the air-filled middle ear to the inner ear which causes movement of the oval window
causing movement of fluid in inner ear
now the movement of the tympanic membrane is changed to fluid
What was the beginning of the transduction in the outer ear?
due to the changing in air pressure into the movement of the tympanic membrane