BL+MCBG Flashcards
What is the rough endoplasmic reticulum?
The Rough Endoplasmic reticulum is a network of membranes in the cell that are covered in ribosomes, and play a role in protein synthesis
Example sentence: The rough endoplasmic reticulum is responsible for synthesizing membrane proteins.
What is the fluid of the cytoplasm called?
The fluid of the cytoplasm is called cytosol and has a pH of 7.2
What are inclusion bodies?
Inclusion bodies are non-metabolically active substances within the cell, such as lipid droplets and metabolites, which do not survive cell division
Main Structure of the plasmalemma?
-Three layers-2 phosoplipid layers-Non-polar (hydrophobic) fatty acid tails of phospholipids go into the middle layer-Polar (hydrophilic) heads located on inner and outer side of the membrane
Function of the peripheral proteins of the plasmalemma?
-Peripheral proteins adsorb so inner and outer si de of the membrane-Involved in cell recognition and interactions
Function of integral proteins of the plasmalemma?
-Integral proteins go through the width of the membrane-regulate passage and materials and active transport
Describe the structure of a mitochondrion?
-Outer, sieve-like membrane and inner folded membrane, separated by intermembranous space-Inner membrane has finger-like folds called cristae-Space deep within the inner membrane is called the matrix-Integral proteins on inner/outer membranes provide passage for small molecules-Matrix has some chromosomes, ribosomes and RNA in order to synthesise a small amount of proteins
What does the number of cristae in a mitochondrion correspond to?
The number of cristae in a mitochondrion corresponds to the energy needs of the cell
Why are mitochondria eosiniophillic?
Mitochondria are stained by eosin due to the high content of mitochondrial DNA
Structure of a ribosome?
-Small, electron dense particles-Made of RNA and 80 different proteins-Exist in three different forms
-polyribomse, isolated cell, RER
Which form of ribosomes synthesises cytosolic (free) proteins?
Polyribsomes synthesise cystosolic proteins
Which form of ribosomes synthesises secretory and endoplasmic reticulum proteins?
Rough Endoplasmic Reticulum (ER with ribosomes adsorbed) synthesises secretory and endoplasmic reticulum proteins
Why are ribosomes called basophillic?
Ribosomes are basophillic because they are stained by most basic dyes
Lyosomes
-membrane bound organelle-for cellular digestion and recycling of cell components-contains (mostly) acid hydrolase enzymes; protease, nuclease, phosphate sets, phospholipases, sulphatases, beta-glucuronidases-theses enzymes are active in cytosol due to 7.2 pH-lysosomes made in golgi
Peroxisomes
-membrane bound organelles -contain enzyme-utilise oxygen without ATP-oxidise organic substrates by removal of H+, which produces H2O2, which is broken down by peroxisomal catalase-peroxisomes are involved in lipid metabolism
Difference between negative and positive feedback loop?
Positive; stops when stimulus ceases i.e regulation of blood clotting
definition of acidosis
Imbalance in which arterial blood pH is below normal (< 7.35)
Control centre for temp regulation pathway
Hypothalamus
How to calculate pH
pH = -log[H+]
stages of a feed back loop
Stimuli, sensor, control centre, effector
Alkalosis
pH above 7.45
Healthy pH ranges
Arterial blood ; 7.45
Venous blood ; 7.35
pH range outside of which death is likely?
6.8-8
Acidosis symptoms
Headache, tired, confusion, tremors, coma
Cause of metabolic acidosis
Build up of metabolic acids either due to increased production or inability to excrete them
cause of respiratory acidosis
Build up of CO2 due to hypoventilation; can occur as a response to metabolic alkalosis
Treatment of acidosis
Bicarbonate infusion
mechanical Ventilation if respiratory
How is the stomach wall protected against the high pH of stomach acid?
Specialised epithelial cells (goblet cells) of the stomach lining secrete mucus
Best treatment for when stomach acid damages oesophagus
anatacids containing weak bases, preferably aluminium hydroxide as this is mild, long lasting and has less side-effects due to being insoluble
What percentage by weight is the human body?
60%
What proportion of body water is intracellular fluid?
2/3
What proportion of body water is extracellular fluid?
1/3
What proportion of extracellular fluid is interstitial fluid?
3/4 of extracellular fluid, 15% body weight
What proportion of extracellular fluid is blood plasma?
Blood plasma makes up 1/4 of extracellular fluid, 5% of body weight
Water in the transmembrane space
-0.5
What percentage by weight is the human body?
60%
60% of body weight is water
What proportion of body water is intracellular fluid?
2/3
2/3 of body water is intracellular fluid
What proportion of body water is extracellular fluid?
1/3
1/3 of body water is extracellular fluid
What proportion of extracellular fluid is interstitial fluid?
3/4 of extracellular fluid, 15% body weight
3/4 of extracellular fluid, equivalent to 15% of body weight, is interstitial fluid
What proportion of extracellular fluid is blood plasma?
Blood plasma makes up 1/4 of extracellular fluid , 5% of body weight
Blood plasma makes up 1/4 of extracellular fluid, which is equivalent to 5% of body weight
Water in the transmembrane space
-0.5 litres (not counted as intra or extracellular fluid)
Water in the transmembrane space is not counted as either intra or extracellular fluid and is approximately -0.5 litres
Standard amount of blood in a 70kg man
5L
A standard amount of blood in a 70kg man is 5 liters
Four types of body tissue and an example of each
epithelial, simple squamous epithelium
Example of epithelial tissue is simple squamous epithelium
connective, adipose tissue
connective, adipose tissue
Example of connective tissue is adipose tissue
Muscle, skeletal muscle
Muscle, skeletal muscle
Example of muscle tissue is skeletal muscle
nervous, neurons
nervous, neurons
Example of nervous tissue is neurons
Limit of resolution
Measurement of how far 2 points must be before the microscope can view them as separate. The smaller D is the better.
Measurement of how far 2 points must be before the microscope can view them as separate. The smaller D is the better.
Limit of resolution is proportional to…
Limit of resultion is proportional to wavelength of viewing light
Limit of resolution is proportional to the wavelength of viewing light
Needle methods for tissue procurement
+Fine needle aspiration suspicious lumps
+venepuncture for a blood sample
+pipelle for (uterus lining)
+trephine for bone marrow
Needle methods for tissue procurement include fine needle aspiration for suspicious lumps, venepuncture for a blood sample, pipelle for uterus lining, and trephine for bone marrow
Explain the value of histology in diagnosis
- Disease Identification: Histological analysis allows for the identification of disease processes at the cellular level. For example, it can distinguish between benign and malignant tumors, helping to confirm diagnoses such as cancer.
- Tissue Characterization: By examining the morphology of cells and their arrangement in tissues, histology can provide insights into the type of disease present. Different diseases often have characteristic histological features that can aid in diagnosis.
- Treatment Planning: Histological findings can inform treatment decisions. For instance, the presence of certain biomarkers in a tumor can indicate the likely effectiveness of targeted therapies.
- Monitoring Disease Progression:
- Research and Development:
Explain why tissues need to be fixed and state which fixatives are commonly used
Tissue samples need to be fixed to preserve their structure and cellular details
Fixation stabilizes the tissues by cross-linking proteins and halting enzymatic degradation, preventing autolysis and putrefaction.
- Collection: Tissue samples are collected as soon as possible to minimize degradation.
-
Choice of Fixative: A suitable fixative is selected based on the intended analysis. Common fixatives include:
- Formalin (usually 10% formalin, which is a buffered solution of formaldehyde) for general histology.
- Glutaraldehyde for electron microscopy, as it preserves ultrastructure well.
- Alcohols for certain cytological preparations.
Describe how tissue processing can lead to shrinkage and other artefacts
Tissue processing is a critical step in preparing samples for microscopic examination, but it can introduce artifacts, including shrinkage, that can affect the interpretation of results. Here’s how these issues can arise:
- Dehydration: During processing, tissues are dehydrated using increasing concentrations of alcohol. This step removes water, causing tissues to shrink. The extent of shrinkage depends on the type of fixative used and the dehydration protocol.
- Embedding Media: The embedding process often involves infiltrating tissues with paraffin or resin. If tissues are not adequately infiltrated or if the embedding medium has a different refractive index, it can result in further shrinkage or distortion.
- Crumpling and Wrinkling: If tissues are not properly fixed or are subjected to mechanical stress during handling, they may become crumpled or wrinkled. This can obscure cellular details.
- Loss of Cytoplasmic Components: Over-fixation or prolonged exposure to fixatives can lead to the loss of important cellular components, resulting in empty spaces or reduced staining intensity.
- Artifactual Spaces: During dehydration and embedding, air can become trapped in the tissue, creating artificial spaces that can be misinterpreted as pathological changes.
- Differential Shrinkage: Different components of the tissue (e.g., fat, muscle, connective tissue) may shrink at different rates, leading to altered morphology that does not reflect the original tissue architecture.
What is immunohistochemistry?
Immunohistochemistry (IHC) is a lab technique used to visualize the presence and localization of specific proteins in tissue sections. It involves the use of antibodies that bind to the target proteins, allowing researchers and pathologists to identify and study cellular structures and functions.
IHC is widely used in clinical diagnostics, particularly in cancer pathology, to help determine the presence of specific markers that can inform treatment decisions.
Tissue procurement methods
Surgical removal
scraping
needle
transvascular
patient collection
Methods of tissue procurement include surgical removal, scraping, needle methods, transvascular collection, and patient collection
Transvascular tissue procurement
Insert wire/catheter into blood vessel then travel to target site to collect sample, tissue needs good vascular supply, used in heart, lung, liver tissue
Transvascular tissue procurement involves inserting a wire or catheter into a blood vessel to travel to the target site for sample collection, suitable for tissues with good vascular supply such as heart, lung, and liver tissue
Stages of preparing tissue for examination
Procurement
fixation
embedding
cutting into slices
staining
microscope exam
Stages of preparing tissue for examination include procurement, fixation, embedding, cutting into slices, staining, and microscope examination
Tissue procurment methods
Surgical removal
scraping
needle
transvascular
patient collection
These are methods used for obtaining tissue samples for clinical diagnostics.
Transvascular tissue procurement
Insert wire/catheter into blood vessel then travel to target site to collect sample, tissue needs good vascular supply, used in heart, lung, liver tissue
This method involves inserting a wire or catheter into a blood vessel to collect tissue samples.
Stages of preparing tissue for examination
Procurement
fixation
embedding
cutting into slices
staining
microscope exam
These are the steps involved in preparing tissue samples for examination.
Haematoxylin
Basic dye
blue/purple
binds to acidic cell structures
Haematoxylin is a basic dye that binds to acidic cell structures.
Eosin
Pink/red
acidic dye
binds to basic cell structures
Eosin is an acidic dye that binds to basic cell structures.
osmolality of blood
285-295 mOsm/kg, (millimoles per kg)
Osmolality is the total number of solute particles per kilogram of blood.
If some NaCl at 40mOsm if added to a solution, how to calculate new osmolality?
Add 40 mOsm for Cl and 40 mOsm for Na!!!
This is the calculation for determining the new osmolality after adding NaCl to a solution.
Oedema
-body fluid becomes dilated
-reduction in [Na] in extracellular fluid
-water moves into cells
-cells/tissues swell
Oedema is characterized by the swelling of cells and tissues due to fluid accumulation.
Best way to measure temp in child under 4 weeks old
Electric thermometer in axilla
This is the recommended method for measuring temperature in infants under 4 weeks old.
Severe hypothermia
28-32 degrees
rigid muslces, no shivering
slow/weak pulse
drowsiness
Severe hypothermia is indicated by low body temperature and symptoms like rigid muscles and drowsiness.
Mild hypothermia
32.1-35
shivering
fatigue
slurred speech
confusion
stiffness
Mild hypothermia is characterized by shivering and symptoms like fatigue and confusion.
Arterial blood gases
A test performed on arterial blood to determine levels of oxygen, carbon dioxide, and pH
Arterial blood gases are used to assess the levels of oxygen, carbon dioxide, and pH in the blood.
Haemtocrit
Percentage by volume of red blood cells in blood
Haemtocrit measures the percentage of red blood cells in the blood.
aquaporin
A membrane protein, specifically a transport protein, that facilitates the passage of water through channel proteins.
Aquaporin is a protein that aids in the movement of water across cell membranes.