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
Match the following:
🅰️Apolar neuron 1️⃣Dorsal root ganglia of spinal cord
🅱️Unipolar neuron. 2️⃣Most of CNS and PNS neurons
🆎Multipolar neuron. 3️⃣Late embryo’s
🆑Pseudo unipolar 4️⃣Early embryos
🅰️4️⃣
🅱️3️⃣
🆎2️⃣
🆑1️⃣
Do axons of CNS have neorolemma?
Axons of CNS have NO NEUROLEMMA.
Because myelin sheath over the axons of CNS is established by oligodandrocyte…while neurolemma is established by neurolemocytes/schwann cells
Which neuroglial cells are mesodermal in origin?
Microglial cells.
- they are monocyte derived.
- they are tissue macrophages(phagocyte) of CNS.
- cells of immune system.
_________cells form BBB(blood brain barrier).
Astrocytes.(largest neuroglial cells).
In PNS myelinated sheath is established by
Neurolemocytes or Schwann cells.
They lay whorls of membrane around the axon and ONLY THE INNER membrane of neurolemocytes is MADE OF “SPHINGOLIPIDS” (lipid bilayer).FINAL layer with cytoplasm and nucleus forms NEUROLEMMA.
In CNS, myelin sheath is formed by ____________.
Oligodendrocytes.(type of neuroglial cells).
Term epithelium was coined by
Ruaysh .
Epithelium is avascular.
T/F
True.
Epithelium has no ground substance or matrix.
T/F
True.
Simple squamous epithelium is aka
Pavement epithelium.
Squamous epithelium is found in
Alveoli of lungs.
Descending loop of Henle.
Endothelium of blood vessel.
Mesothelium(epithelium of coelomic cavity).
Simple ciliated cuboidal is found in
Ascending limb loop of henle.
Simple pigmented epithelium is found in
Retina of the eye.
Simple germinal cuboidal is found
Gonads.
Simple brush bordered cuboidal epithelium is found in
proximal convulated tubule
distal convulated tubule
Simple ciliated columnar epithelium
Ependyma (epithelium that lines ventricles of brain)
Fallopian tube
Buccopharyngeal cavity of frogs(+ve pressure breathing)
Brush bordered columnar epithelium is found in
Epithelium of intestines (absorption)
Sensory columnar epithelium is found in
Olfactory mucosa of nose (schilinidarian membrane )
Taste buds
Name endocrine glands?
Ductless glands.. Thyroid Pituitary Adrenal Hypothalamus
Pnemonic = path
Name exocrine glands?
Drain their secretion into the body surface.. Salivary glands Gastric glands Oil glands Mammary glands Tear glands Intestinal glands
Pmeumonic= Tsimog
Name heterocrine glands?
Liver
Pancreas
Gonads
Pnemonic=LPG
Name a unicellular gland?
Goblet gland (mucous secreting cells/gland).
Total loss of cell occurs in which way of secretion?
Apocrine
Merocrine
Holocrine
Holocrine (cell ruptures to give out secretory granules alongwith cell debris). # Shown by oil glands.
Holo means complete.
No loss of cell occurs in
Holocrine
Apocrine
Merocrine
Merocrine (secretory granules are released by diffusion or endocytosis). # shown by pancreas, intestinal glands, salivary glands & sweat glands.
Partial loss of cells occur in
Holocrine
Merocrine
Apocrine
Apocrine (secretory granules—>contriction—>separate—>burst). # shown by mammary glands.
Pseudo-stratified ciliated epithelium is found in
Major and minor bronchi.
Pseudo-stratified non-ciliated epithelium is found in
Parts of urethra
Parotid gland duct i.e stensons duct.
Compound epithelium is found in
Skin, oesophagus, anal canal, vaginal canal etc.
Which epithelium plays role in regeneration of epithelium ?
Stratified compound epithelium
What is stratum germinatavum?
1st layer of cells over the basement membrane of stratified compound epithelium are mostly columnar and are c/d stratum germinatavum.
Whats stratum coroneum?
Dead top layer of keratinised epithelium is c/d stratum coroneum.
Transition epithelium is found in
Urinary bladder, penile urethra, uretors, renal pelvis, uterus (during 3rd trimister).
Give the location of keratinised and non-keratinised epithelium
Keratinised: epithelium of skin
Non-keratinised: buccal cavity, anal canal, vaginal canal, oesophagus.
What are gap junctions?
Cells are connected by a protein c/d conexon.
for example: voltage synapse, intercalated disc, b/w smooth muscles.
What is intermediate junction?
Junctions that along with tight junctions maintain cellular integrity.
Have 3 types = adhering, desmosomes, hemidesmosomes.
What are tight junctions (zonula occludens)?
Junctions where membrane of cells in vicinity fuse.
* form water tight seal.
E.g., stomach, intestine, urinary bladder.
What are Adhering junctions (zonula adherins)?
Connection through Adhesion belt (catanins alongwith condensed cytoplasm is called adhesion belt).
*catanins r proteins.
What are Desmosomes (macula adherens).
Desmosomes are adhering junctions but instead of actin they’ve keratin, c/d tonofibrils. # adhesion belt is lateral.
In hemidesmosomes adhesion belt is?
Adhesion belt is basal. # connect epithelium to basement membrane.
