Histology- Animal tissues(structural organisation in animals) Flashcards
What are tissues?
Group of cells with similar origin, structure, function and show division of labour.
Though there are some exceptions…
Name the tissue where the cells dont have similar structure.
Blood (RBC’s, WBC’s, platelets- all have different structure though they make up a tissue)
Name the tissue whose cells perform different functions?
Blood.
RBC’s help in transport of gases,
WBC’s in resistance or immunity,
Platelets in clotting
Term tissue was coined by
Francisco Marie Xabier Bichat in 1792.
Biogenesis of tissue is called
Histogenesis
Nervous tissue is ________in origin.
Ectodermal.
from the epineural cleft of embryo.Neurula stage of embryo consists of epineural cleft from which retina, nervous tissue originate.
Which part is the interpreting centre of a neuron?
Cell body.
As it contains nucleus,
# It has all organelles except centrioles. Its absent in mature neuron as it helps in division but neurons do not divide in mature form(lack of regeneration).
Whats the role of lipofusing granules?
Play major role in ageing i.e their concentration increases with age.
If its controlled average age of man can increase by 80%.
Nissles granules are
Granular form of ER that has ribosomes attached to it.
Plays role in protein synthesis and modulation.
Are dendrites converging or diverging? Also state why .
Dendrites are converging as they converge the info. (sensory) from all sites towards the cyton.
Length of axon ranges from _________in ANS to _______ in PNS.
Few millimeters in CNS to
Few metres in PNS.
Are axons converging or diverging? Why so.
Axons are diverging as they carry info. (motor) away from cyton.
* they are devoid of nissles granules.
Rate of transport in Cytoplasmic streaming is
1mm/day.
These are directional movt. that occur always “from cyton to axon”.
Rate of transport in axonal flow is?
300mm/day.
Its bidirectional i.e from cyton to axon and back.
It happens along the neurofibrils.
Faster than cytoplasmic streaming movt.
Rabies virus enters through cytoplasmic streaming movt.
True.
Do unmylenated neurons have neurolemocytes/ neurolemma ?
Yes .
But they dont lay whorls of membrane around axon.
At node of Ranvier:
▪️neurolemma of the 2 neurolemocytes fuse to form a continuous sheath.
▪️mylein sheath is discontinuous.
Which one of them is correct.
Both are correct.
Talodandriya is : ▪️collective name for synaptic bulb and axon terminal. ▪️aka terminal arborisation. ▪️both of these ▪️none of these
Both of these
Neurotransmitters are
▪️Extrinsic
▪️Intrinsic
▪️Neither extrinsic nor intrinsic
Extrinsic messengers.
Extrinsic messengers ➡️ Receptor ➡️ Intinsic messenger ➡️ Intended response
Resting membrane character is ▪️More permeable for K+ ▪️Less permeable for Na+ ▪️K+ channels open ▪️Na+ channels close
All of these i.e More permeable for K+, Less permeable for Na+, K+ channels open, Na+ channels close.
_______ and _______ generate or are responsible for generating resting potential i.e -70mV.
Na-K-pump and resting membrane character
At equilibrium,
Na+ ion concentration is ______time than inside &
K+ ion concentration is _____times then outside.
Na+ = 28 times K+ = 14 times
Name few stimulatory neurotransmitters?
Non-epinephrine
Acetylecholine
Name few inhibitory neurotransmitters?
Glysine
GABA(gamma amino butyric acid)
They hyperpolarize the membrane i.e potential varies from -70mV to -90mV.
In ________synapse there is no synaptic cleft.
Voltage synapse.
Since the pre- and post- synaptic membrane are fused.
So there’s NO synaptic delay, NO chance of synaptic fatigue.
Channel protein _____ is used in axon-axon voltage synapse
Connexon