Module Flashcards
What is histology?
The study of tissues and organs, examining the architecture of these structures at the microscopic level and forming links between structure and function of the different tissue and cell types.
What are the disciplines of histology?
- Anatomy –> Structures
- Physiology –> Tissues and cell types (systems)
- Biochemistry –> Cellular reactions/pathways
What are the 4 types of tissues?
Connective, epithelial, muscle and nerve.
What are the general rules of tissue collection?
- Dissection from autopsy/abattoir/ euthanised organisms/plant tissue.
- Biopsy from a clinician.
- Use sharp instruments
- Limited handling
- Within 10 min of slaughter
- Size (1cmx2cmx5mm) maximum
- Into the correct volume of fixative.
Why do we need to fix tissues?
To preserve the chemical and physical characteristics of the tissue. If not done properly it can lead to irreversible damage to the tissue.
Time is important to fix the tissue asap.
Limit loss and diffusion of soluble substances.
How are tissues fixed?
Tissue elements will be: crossed-linked (stabilised and preserved); coagulated/precipitated; chemically unaffected but trapped.
What are the types of tissue fixation?
-Types of fixation = physical or chemical
Physical = heat/microwave/cryopreservation (liquid nitrogen cooled isopentane)
- Chemical = Dehydrant coagulant fixatives (ethanol, methanol, acetone), Non-coagulant fixatives (4% formaldehyde -10% NBF)
Describe tissue embedding in paraffin.
The processed tissue is now removed from the cassette and placed into a metal/plastic mould and covered in liquid paraffin.
The back of the cassette is placed on top and more wax is added.
These are allowed to set to give you paraffin embedded, processed and fixed tissue ready for sectioning.
Describe tissue sectioning in paraffin, the microtome.
The paraffin block is secured into the microtome - set to cut at a certain thickness
~30μm for trimming in the block – removing excess wax.
~3-7 μm for sectioning (takes a lot of practice)
Different tissues types, structures, shapes how well it was fixed and processed plus cutting techniques = bad/good quality sections.
Describe tissue embedding frozen.
Following dissection, the tissue is cut into sections. Place in plastic moulds and fill with embedding matrix (OCT) – Optimum Cutting Temperature.
Float sample on liquid nitrogen cooled isopentane until it solidifies.
Describe the tissue sectioning, frozen OCT in the cryostat.
Set-up is very important
Cutting Temp will need to be varied for different tissue types.
Depends on water and fat content.
Describe the 2 stains: hematoxylin and eosin.
Hematoxylin – Basic, +ve compound and binds to acidic, -ve charges therefore DNA/RNA.
It stains nuclei blue-black showing good intranuclear detail.
Eosin – Acidic, -ve compound and binds basic +ve charges therefore many proteins.
Stains cytoplasm, most connective and muscle tissue fibres different shades and intensities of pink, orange and red.
What is immunohistochemistry?
Target cellular and subcellular localisation of antigens (e.g. proteins) using antibodies.
Antibodies bind small and large antigens with high affinity and specificity.
What is the protein localisation, 2 step indirect method?
- Fixation and Permeabilization - Cells or tissue are fixed to preserve cellular structures and immobilize proteins. Permeabilization is performed to allow antibodies to access intracellular proteins.
- Blocking - The sample is treated with a blocking solution (e.g., 1-5% BSA or serum) to reduce nonspecific antibody binding.
- Primary Antibody Binding - The sample is incubated with a primary antibody that specifically binds to the target protein.
This antibody is usually not labelled and is specific to the protein of interest. - Secondary Antibody Binding - A labelled secondary antibody is added, which binds specifically to the primary antibody.
The secondary antibody is conjugated with a detectable marker, such as: Fluorophores for fluorescent microscopy, Enzymes for for colorimetric detection, Gold particles for electron microscopy. - Visualization - The sample is analysed using an appropriate detection system:
Fluorescence microscopy for fluorophore-labelled antibodies.
Chromogenic substrates for enzyme-labelled antibodies in light microscopy.
Electron microscopy for gold-labelled antibodies.
What is histopathology?
The study of tissues affected by disease, can be very useful in making a diagnosis and in determining the severity and progression of a disease.
Can we view viruses and bacteria under a light microscope?
Bacteria yes, viruses no.
Describe acute inflammation.
Dilation of arterioles - increase in the blood.
Increase in the permeability of capillaries allowing antibodies to enter the tissue.
Migration of leukocytes from the blood into the tissues cells cross the endothelial cells, move out into the tissue.
What is scarring and fibrosis.
Seen when the cells of a tissue are damaged or killed and regeneration of the normal tissue architecture cannot take place
Laying down collagen – not well detected by H&E, better with Masson’s trichrome (stains collagen blue) or with Gieson (stains collagen red/pink).
What is hyperplasia?
Can be a normal physiological response to demand placed on a tissue.
What is dysplasia?
Cells may lose some of their morphological characteristics and/or functions. The tissue becomes disordered, often with an increase in the numbers of immature cells, and greater variability between cells.
What is neoplasia?
Cervical Intraepithelial Neoplasia Increased (CIN). Hyperchromasia
Variation in nuclear size.
Loss of polarity.
Increased mitosis; abnormal mitosis
What is histopathology?
Histopathology is the study of tissues affected by disease, used for diagnosis and assessing disease severity and progression.
Why is understanding normal tissue structure and function important in histopathology?
It helps in interpreting the changes that occur in tissues during disease.
What are the main types of diseases diagnosed using histopathology?
Cancer, inflammatory diseases, benign abnormal growths, and infections.
What are the roles of a clinically qualified histopathologist?
They are responsible for diagnosing diseases based on tissue samples.
How does histology contribute to disease diagnosis?
It can provide definitive diagnoses or support diagnoses alongside biochemical and serological tests.
Why might histology alone be insufficient for diagnosing some diseases?
Some conditions, like encephalitis, show inflammation but require additional testing to identify the specific pathogen.
How is Variant Creutzfeldt-Jakob Disease (vCJD) diagnosed?
Through histology and biochemistry, often performed post-mortem.
Why are viruses difficult to detect using light microscopy in histopathology?
They are too small to be seen; their presence is inferred from tissue inflammation and immunohistochemical markers.
What staining method is used to identify Mycobacterium tuberculosis in histopathology?
Ziehl-Neelsen stain, which differentiates acid-fast bacteria (red) from non-acid-fast bacteria (blue).
What are the key features of acute inflammation?
Dilation of arterioles, increased capillary permeability, and migration of leukocytes (mainly neutrophils) into tissues.
How does chronic inflammation differ from acute inflammation?
Chronic inflammation involves long-term immune cell infiltration, such as lymphocytes, and may lead to fibrosis and scarring.
What is an example of autoimmune-related histopathology?
Lymphocyte infiltration in the islets of Langerhans in Type 1 Diabetes or neuromuscular junction abnormalities in Myasthenia Gravis.
What is the difference between hyperplasia, dysplasia, and neoplasia?
Hyperplasia: Increased cell number, often a normal response to demand.
Dysplasia: Disordered growth with abnormal cells.
Neoplasia: Uncontrolled cell growth, often leading to tumours.
What are the key histological features of Cervical Intraepithelial Neoplasia (CIN)?
Increased cell numbers, hyperchromasia, variation in nuclear size, loss of polarity, and abnormal mitosis.
How can tumour invasion and metastasis be identified in histopathology?
By observing tumour cells breaching normal tissue boundaries, invading blood vessels, and spreading to distant tissues.
What is the GI tract, and what are its main components?
The GI tract is a series of hollow organs forming a continuous tube from the mouth to the anus. Its main components include the mouth, oesophagus, stomach, small intestine, large intestine, and anus.
What are the four main learning outcomes of this lecture?
Recap the different components of the GI tract.
Learn about the microscopic anatomy of the GI tract.
Explore histological images of the GI tract.
Understand GI tract pathologies in relation to histological examination.
What is the primary function of the oesophagus?
The oesophagus is a muscular tube that transports food from the mouth to the stomach using peristalsis.
What is the function of the epiglottis?
The epiglottis prevents food and liquid from entering the trachea during swallowing.
What are the four tunics of the GI tract?
Mucosa – Mucous membrane that acts as a barrier.
Submucosa – Connective tissue joining the musculature to the mucosa.
Muscularis – Responsible for propulsion of food.
Serosa (or Adventitia) – Outer protective covering of the GI tract.
What are the three layers of the mucosa in the oesophagus?
Epithelium – Stratified squamous non-keratinized epithelium.
Lamina propria – Connective tissue supporting the epithelium.
Muscularis mucosae – Thin layer of smooth muscle aiding movement.
How does the histology of the oesophagus differ from that of the stomach?
The oesophagus has stratified squamous epithelium (for protection), while the stomach has simple columnar epithelium (for secretion of gastric juices).
What is the primary histological difference between the duodenum and the jejunum/ileum?
The duodenum has Brunner’s glands in the submucosa, while the jejunum and ileum lack these glands but have more developed villi and Peyer’s patches (immune tissue).
What are common histological features of gastrointestinal cancer?
Features include cellular disorganization, loss of polarity, increased mitotic figures, and invasion of surrounding tissues.
How can deep learning help in the classification of gastrointestinal cancer?
AI and deep learning can analyze histological slides to improve diagnosis and prognostication by detecting subtle patterns in tissue structure.
What histological changes occur in chronic inflammation of the GI tract?
Chronic inflammation can lead to lymphocyte infiltration, tissue remodelling, and fibrosis.
How can you distinguish between the histology of the small intestine and the large intestine?
Small intestine: Has villi and crypts, with goblet cells.
Large intestine: Lacks villi but has deep crypts with numerous goblet cells for mucus secretion.
What are the primary functions of the mucosa, submucosa, and muscularis layers in digestion?
Mucosa: Secretion, absorption, and barrier function.
Submucosa: Support and housing of blood vessels, lymphatics, and nerves.
Muscularis: Propulsion and mechanical digestion through peristalsis.
What are three key histological features used to differentiate the oesophagus, stomach, and duodenum?
Oesophagus: Stratified squamous epithelium, muscularis externa.
Stomach: Simple columnar epithelium, gastric pits.
Duodenum: Villi, Brunner’s glands.
What is the importance of distinguishing different layers and components of the GI tract histologically?
Understanding these layers helps in diagnosing diseases, identifying pathological changes, and determining treatment approaches.
Where are the kidneys located in the body?
The kidneys are located on the dorsal (posterior) side of the body, on either side of the spinal column, between T12 and L3 vertebrae.
What protects the kidneys?
The kidneys are protected by the ribcage, perirenal fat, renal fascia, and fibrous capsule.
What are the key external structures of the kidney?
Renal hilum (entry/exit site for vessels, nerves, and ureter)
Renal capsule (outer protective covering)
Cortex (outer layer)
Medulla (inner region, containing renal pyramids)
What structures are found in the internal anatomy of the kidney?
Renal cortex
Renal medulla (including renal pyramids)
Renal pelvis (funnel-shaped structure leading to the ureter)
Calyces (minor and major calyces collect urine from nephrons)
What is the functional unit of the kidney?
The nephron, which filters blood and forms urine.
What are the two main types of nephrons?
Cortical nephrons (mostly in the cortex, shorter loops of Henle).
Juxtamedullary nephrons (longer loops of Henle, important for urine concentration).
What are the major structures of a nephron?
Glomerulus (filtration site)
Bowman’s capsule (collects filtrate)
Proximal convoluted tubule (PCT) (reabsorption of nutrients)
Loop of Henle (creates concentration gradient)
Distal convoluted tubule (DCT) (further reabsorption)
Collecting duct (final urine processing)
What is the role of the glomerulus?
The glomerulus is a network of capillaries that filters blood, allowing water and small solutes to pass into the nephron while retaining proteins and blood cells.
How does blood enter and leave the glomerulus?
Blood enters via the afferent arteriole.
Blood exits via the efferent arteriole (which leads to the peritubular capillaries or vasa recta).
What is the significance of the glomerular filtration barrier?
It prevents large molecules like proteins and blood cells from passing into the filtrate while allowing water, ions, and small molecules to be filtered.
What is the importance of the vasa recta?
The vasa recta are capillaries that surround the loop of Henle, helping maintain the osmotic gradient necessary for water reabsorption.
How does the kidney receive its blood supply?
Blood enters through the renal artery.
It flows through segmental arteries → interlobar arteries → arcuate arteries → afferent arterioles → glomerulus.
Blood leaves via efferent arterioles → peritubular capillaries/vasa recta → renal vein.
What are the three main processes in urine formation?
Glomerular filtration (blood plasma filtered into nephron).
Tubular reabsorption (useful substances reabsorbed into blood).
Tubular secretion (waste and excess ions secreted into filtrate).
What role does the loop of Henle play in urine concentration?
The descending limb allows water reabsorption, while the ascending limb pumps out Na⁺ and Cl⁻, creating a concentration gradient in the medulla.
How does the kidney help maintain homeostasis?
The kidney regulates:
Water balance (via ADH hormone).
Electrolytes (Na⁺, K⁺, Cl⁻, HCO₃⁻).
Acid-base balance (pH regulation).
Blood pressure (via renin-angiotensin system).
Where is the liver located in the human body?
The liver is located in the upper right quadrant of the abdomen, beneath the diaphragm, and protected by the rib cage.
What are the main lobes of the liver?
Anterior view: Two lobes (right and left) separated by the falciform ligament.
Posterior view: The right lobe is further divided into the quadrate lobe and caudate lobe.
What are the three major blood vessels associated with the liver?
Hepatic portal vein (HPV) → Brings nutrient-rich blood from the gastrointestinal tract, pancreas, and spleen.
Hepatic artery (HA) → Brings oxygenated blood from the aorta.
Hepatic veins → Carry deoxygenated blood from the liver to the vena cava.
How does blood enter and exit the liver?
Blood enters via the hepatic portal vein (nutrient-rich) and hepatic artery (oxygenated).
Blood flows through sinusoids, allowing exchange with hepatocytes.
Blood exits via the hepatic veins into the inferior vena cava.
What is the functional unit of the liver?
The hepatic lobule, a hexagonal structure centered around a central vein with surrounding portal triads.
What are the key structures of a hepatic lobule?
Central vein (drains blood from the lobule).
Portal triad (hepatic artery, hepatic portal vein, bile duct).
Sinusoids (capillary-like structures where blood flows around hepatocytes).
Hepatocytes (main functional cells of the liver).
What is the Couinaud system?
A classification system dividing the liver into 8 segments based on vascular supply.
What is the function of bile?
Bile aids in the digestion and absorption of fats by emulsifying lipids and eliminating waste products like bilirubin.
How does bile flow from the liver to the small intestine?
Hepatocytes secrete bile into bile canaliculi.
Bile drains into bile ducts → right & left hepatic ducts → common hepatic duct.
Bile is stored in the gallbladder via the cystic duct.
During digestion, bile is released through the common bile duct into the duodenum via the sphincter of Oddi.
What are the major ducts in the biliary system?
Right and left hepatic ducts
Common hepatic duct
Cystic duct (connects to gallbladder)
Common bile duct (empties into the duodenum)
What are the main functions of the liver?
Metabolism (carbohydrates, lipids, proteins).
Detoxification (removes toxins, drugs, alcohol).
Bile production (fat digestion).
Storage (glycogen, vitamins, iron).
Synthesis of plasma proteins (albumin, clotting factors).
How does the liver regulate blood glucose levels?
High blood glucose → Liver stores glucose as glycogen (glycogenesis).
Low blood glucose → Liver breaks down glycogen to release glucose (glycogenolysis).
Prolonged fasting → Liver produces glucose from non-carbohydrates (gluconeogenesis).
How does the liver detoxify harmful substances?
Phase I metabolism (modification via cytochrome P450 enzymes).
Phase II metabolism (conjugation with molecules to make substances water-soluble for excretion).
What are the three zones of the hepatic lobule, and how do they differ?
Zone 1 (periportal): Closest to the hepatic artery, receives oxygen-rich blood, and is active in oxidative metabolism.
Zone 2 (midzone): Intermediate oxygen supply, involved in both metabolism and detoxification.
Zone 3 (centrilobular): Closest to the central vein, receives least oxygen, involved in detoxification and vulnerable to hypoxia.
What are Kupffer cells, and what is their function?
Kupffer cells are liver macrophages found in sinusoids that remove bacteria, debris, and aged red blood cells from the bloodstream.
Where are the ovaries located in relation to the uterus?
The ovaries are located on either side of the uterus, connected to it by the ovarian ligament and supported by the broad ligament and suspensory ligament.
What are the two main regions of the ovary?
Cortex – Contains follicles at different stages of development.
Medulla – Contains blood vessels, lymphatic vessels, and nerves.
What is the function of the broad ligament?
The broad ligament supports the ovaries, uterus, and fallopian tubes and contains blood vessels, nerves, and lymphatics.
What does the suspensory ligament contain?
The suspensory ligament contains the ovarian artery and vein, nerves, and lymphatic vessels, which supply the ovary.
What is the role of the ovarian ligament?
The ovarian ligament connects the ovary to the uterus, keeping it in place.
What is angiogenesis, and where does it occur in the ovary?
Angiogenesis is the formation of new blood capillaries. It occurs in the growing follicles and corpus luteum to support hormone production.
What are the five types of pre-antral follicles?
Primordial follicle
Primary follicle
Secondary follicle
Tertiary follicle
Pre-antral follicle
What is an antral follicle, and what significant cell types does it contain?
An antral follicle is a mature follicle with a fluid-filled cavity (antrum) and contains:
Theca cells (produce androgens)
Granulosa cells (convert androgens to estrogen)
Oocyte (developing egg).
What is the function of theca cells?
Theca cells produce androgens, which are later converted into estrogen by granulosa cells.
What is the function of granulosa cells?
Granulosa cells convert androgens into estrogen and provide nutritional support to the oocyte.
What is the corpus luteum, and what is its role?
The corpus luteum is a temporary endocrine structure formed after ovulation. It secretes progesterone to maintain the uterine lining for pregnancy.
What happens to the corpus luteum if pregnancy does not occur?
If pregnancy does not occur, the corpus luteum degenerates into the corpus albicans, and progesterone levels decline.
Where does the ovary receive its blood supply from?
The ovary receives blood from the ovarian artery, which originates from the abdominal aorta.
At what stage is the oocyte arrested in meiosis before ovulation?
The oocyte is arrested at Metaphase II until fertilization occurs.
What is the importance of histological studies of the ovary?
Histological studies help identify follicular development stages, cell types, and pathological changes in ovarian function.
Where are the testes located in the male reproductive system?
The testes are located in the scrotum, outside the body cavity, to maintain a lower temperature for optimal sperm production.
What are the primary functions of the testes?
The testes have two main functions:
Spermatogenesis – The production of sperm.
Hormone secretion – The production of testosterone by Leydig cells.
What are the main structures of the testis?
The testes consist of:
Tunica albuginea – A dense connective tissue capsule.
Septa – Divide the testis into lobules.
Seminiferous tubules – The site of sperm production.
Epididymis – Stores and matures sperm.
What is the pathway of sperm from production to ejaculation?
Seminiferous tubules → 2. Epididymis → 3. Ductus deferens → 4. Ejaculatory duct (mixes with secretions from seminal vesicle & prostate) → 5. Urethra → 6. Ejaculation.
What are the main stages of spermatogenesis?
Spermatogonia (stem cells)
Primary spermatocytes (2N)
Secondary spermatocytes (N)
Spermatids (round cells)
Spermatozoa (mature sperm)
What is the role of Sertoli cells in the testes?
Sertoli cells provide nutritional and structural support to developing sperm, form the blood-testis barrier, and secrete inhibin, which regulates FSH levels.
What is the function of Leydig cells?
Leydig cells, located outside the seminiferous tubules, produce testosterone, which is essential for spermatogenesis and male secondary sexual characteristics.
What are the different types of spermatogonia, and what do they do?
Type A (dark) stem cells – Reserve cells that do not undergo mitosis.
Type A (light) stem cells – Actively divide to maintain the sperm-producing pool.
Type B cells – Differentiate into primary spermatocytes.
What happens during spermiogenesis?
Spermiogenesis is the final step in sperm development, where round spermatids transform into spermatozoa by developing:
A tail for motility
An acrosome for egg penetration
A compact nucleus
What is the role of the epididymis?
The epididymis is responsible for sperm storage, maturation, and transport. Sperm gain motility and the ability to fertilize an egg here.
What is the function of the ductus deferens?
The ductus (vas) deferens transports sperm from the epididymis to the ejaculatory duct, using peristaltic contractions.
What is the role of the seminal vesicles in semen production?
The seminal vesicles contribute fructose-rich fluid that provides energy for sperm and makes up 60% of semen volume.
What is the function of the prostate gland?
The prostate gland secretes an alkaline fluid that helps sperm survive in the acidic vaginal environment.
What is the function of the bulbourethral glands?
These glands secrete a mucus-rich pre-ejaculate that lubricates the urethra and neutralizes acidity before ejaculation.
What is the role of testosterone in male reproductive function?
Testosterone is essential for:
Spermatogenesis
Male secondary sexual characteristics (e.g., deep voice, muscle growth)
Libido and reproductive behaviour.
What are the two main components of the central nervous system (CNS)?
The brain and spinal cord.
What are the main anatomical parts of the CNS?
Cerebrum – Higher cognitive functions
Cerebellum – Coordination and balance
Brainstem – Autonomic functions
Spinal cord – Communication between brain and body
What are the main types of cells found in the CNS?
Neurons – Signal transmission
Astrocytes – Support and nutrient supply
Oligodendrocytes – Myelin production
Microglia – Immune defense
Ependymal cells – Line ventricles and produce cerebrospinal fluid (CSF)
What is the basic structure of a neuron?
Cell body (soma) – Contains the nucleus
Dendrites – Receive signals
Axon – Transmits electrical impulses
Axon terminals – Release neurotransmitters
What is the function of astrocytes in the CNS?
Astrocytes maintain the blood-brain barrier, regulate ion balance, and provide structural support.
What is the role of oligodendrocytes?
Oligodendrocytes produce myelin, which insulates axons and speeds up nerve signal transmission.
What is the function of microglia in the CNS?
Microglia act as the immune cells of the CNS, removing pathogens and damaged cells.
What is the role of ependymal cells?
Ependymal cells line the ventricles of the brain and help produce and circulate cerebrospinal fluid (CSF).
What is the purpose of myelin in the CNS?
Myelin insulates axons, allowing faster electrical signal transmission along neurons.
What are the main staining techniques used for CNS histology?
H&E stain – Stains nuclei blue, difficult to differentiate structures
Nissl stain – Binds RNA, highlights cell bodies
Golgi (silver) stain – Stains a few neurons at random, shows morphology
Gold chloride stain – Stains astrocytes intensely
What is the advantage of using Nissl stain in CNS histology?
Nissl stain highlights neuronal cell bodies by binding to RNA, making it useful for studying neuron structure.
Why is the Golgi stain useful for studying neurons?
The Golgi stain randomly stains a few neurons, allowing detailed visualization of their morphology.
What is the blood-brain barrier (BBB), and why is it important?
The BBB is a selective barrier formed by astrocytes that protects the brain from toxins and pathogens while allowing essential nutrients to pass.
What is cerebrospinal fluid (CSF), and what is its function?
CSF is a clear fluid produced by the ependymal cells that provides cushioning, nutrient transport, and waste removal in the CNS.
What is the difference between white matter and gray matter in the CNS?
White matter consists mainly of myelinated axons, allowing fast signal transmission.
Gray matter contains neuron cell bodies, where processing and integration occur.
What are the main gross anatomical parts of the Central Nervous System (CNS)?
The brain and spinal cord.
What are the main cell types found in the CNS?
Neurons, astrocytes, oligodendrocytes, microglia, and ependymal cells.
What are the basic components of a neuron?
The cell body (soma), dendrites, and axon.
What is the primary function of astrocytes?
Astrocytes support neurons, regulate the blood-brain barrier, and maintain the extracellular ion balance.
What do oligodendrocytes do in the CNS?
They form the myelin sheath around axons, which speeds up electrical signal transmission.
What role do microglia play in the CNS?
Microglia act as immune cells, removing damaged neurons and defending against infections.
What is the function of ependymal cells?
They line the ventricles of the brain and help circulate cerebrospinal fluid (CSF).
What does the Hematoxylin and Eosin (H&E) stain highlight?
Nuclei stain blue, and rough endoplasmic reticulum stains dark blue; dendrites and axons stain pink/purple.
What is the purpose of the Nissl stain?
It binds to RNA, providing good definition of the cell body and highlighting the rough endoplasmic reticulum.
What does the Golgi (silver) stain reveal?
It randomly stains a limited number of neurons and their processes, making it useful for studying cell morphology.
What is the Gold chloride stain used for?
It specifically stains astrocytes, but the intensity can make interpreting the underlying structures challenging.
How are neurons categorized based on shape?
Neurons come in various shapes and sizes, including multipolar, bipolar, and unipolar forms.
Why is the Golgi stain important in neuroscience?
It allows visualization of the entire structure of some neurons, aiding the study of their morphology.
What should you be able to describe regarding CNS morphology?
The gross structure of the brain and spinal cord, including major anatomical regions and their functions.
Why are specialized stains important in studying the CNS?
Different stains highlight specific cell types and structures, allowing researchers to distinguish between various cellular components of the CNS.
What is the Peripheral Nervous System (PNS)?
The PNS consists of all nerves and ganglia outside the brain and spinal cord, connecting the CNS to limbs and organs.
How many cranial nerves are there in humans?
There are 12 pairs of cranial nerves.
What functions do cranial nerves serve?
Cranial nerves can be sensory, motor, autonomic, or a combination of these functions.
How many pairs of spinal nerves are there?
There are 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.
What types of information do spinal nerves carry?
Most spinal nerves carry sensory, motor, and autonomic information.
What are the main cell types found in the PNS?
Neurons, Schwann cells, satellite cells, and macrophages.
What is the function of Schwann cells?
They form the myelin sheath around peripheral nerve fibers, aiding in faster electrical signal transmission.
What role do satellite cells play in the PNS?
They provide structural and metabolic support for neurons in ganglia.
What is a ganglion in the PNS?
A ganglion is a collection of neuron cell bodies where synaptic connections occur, especially in the autonomic nervous system.
What are peripheral nerves composed of?
Bundles of nerve fibers, including axons from sensory and motor neurons, surrounded by connective tissue layers.
What is the autonomic nervous system?
A subdivision of the PNS responsible for involuntary functions, such as heart rate, digestion, and respiratory rate.
How are cranial nerves classified by function?
They are categorized as purely sensory, purely motor, or mixed (both sensory and motor functions).
What is the role of macrophages in the PNS?
They clear cellular debris and help repair damaged nerves.
What mnemonic helps remember the order of cranial nerves?
A common mnemonic is “Oh, Oh, Oh, To Touch And Feel Very Green Vegetables, AH!” (Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal).
What is the primary function of spinal nerves?
They transmit signals between the spinal cord and the rest of the body, managing both voluntary movements and involuntary functions.
