Learning outcomes Flashcards
Define aetiology
Cause of disease
Define pathogenesis
How a disease develops
Define signs
What the doctor sees
Define symptoms
What the patient feels
Define diagnosis
Determining the nature and cause of disease
Define prognosis
A prediction of the probable outcome of the disease
What are the classifications of disease?
Growth Unnatural Degenerative Developmental Inflammation Circulatory
What proportion of the body’s water is in the ECF and ICF?
ECF= 1/3 ICF= 2/3
What proportion of ECF is ISF and plasma?
ISF= 80% Plasma= 20%
What is negative feedback control?
A change is detected by receptors, which is then fed to an integration level and compared to a reference level. A difference causes a signal to be sent to an effector and the change is negated
What is feed forward control?
Changes can be anticipated and negated before they occur
What is the first law of thermodynamics?
Energy can be converted from one form to another but not created or destroyed
What is the second law of thermodynamics?
All energy transformations ultimately lead to more entropy in the universe
How do cells maintain order if the laws of thermodynamic state they should not?
Even though the processes create more ordered, the heat that is released into the environment creates more entropy overall
Why is equilibrium not reached in biological reaction pathways?
Products from one reaction are used in the next reaction in the pathway
What is dynamic steady state?
The concentrations are constant but equilibrium is not reached
Define metabolism
The chemical processes in a living organism that allow food to be used for tissue growth
Define catabolism
Releases energy, negative G, spontaneous
Define anabolism
Require energy, positive G, not spontaneous
What are the uses of ATP and ADP in metabolic processes?
Act as free energy carriers, coupling anabolic and catabolic reactions using phosphate group transfers
What are the functions of NADP/NAD and FAD in metabolic processes?
Used in reduce reactions as electron carriers
What are the major elements used to construct human biomolecules
O H C N Na Cl K Ca S P
What is the importance of functional groups?
Affect how a molecule acts around others
What is molecular configuration?
The fixed arrangement of atoms in a molecule
What is molecular conformation?
The precise arrangement of atoms in molecule
What are the 5 types of chemical reactions in the body?
Redox Making/breaking C-C bonds Internal rearrangements Group transfers Condensation/hydrolysis
Give an example of a redox reaction in the body
Glycolysis in muscles
Give an example of making/breaking C-C bonds in the body
Cleavage of glucose in glycolysis
Give an example of internal rearrangement reactions in the body
Glucose-6-phosphate–> fructose-6-phosphate in glycolysis
Give an example of a group transfer reaction in the body
Transfer of phosphate group in glycolysis
Give an example of a condensation/hydrolysis reaction in the body
Formation and breaking of nucleic acids and proteins
Describe the structures present in all cells
Nucleus
Cytoplasm
What are the roles of the nucleus in eukaryotic cells?
Contains DNA, nucleoprotein and some RNA
What is the function of the nucleoli?
Sites for ribosomal synthesis and assembly
What is the endoplasmic reticulum?
Interconnecting network of membranous tubules, vesicles and cisternae
What are the two forms of the endoplasmic reticulum?
Rough ER
Smooth ER
What is the function of the rough endoplasmic reticulum?
Synthesises and packages proteins
What is the function of the smooth endoplasmic reticulum?
Lipid biosynthesis and membrane synthesis and repair
What is the function of ribosomes?
Protein factories
What is the golgi apparatus and its function?
Stack of flattened vesicles that package and process secretory proteins and synthesise complex polysaccharides
What are lysosomes and their function?
Membrane bound organelles containing granular materials used to break down bacteria and debris
What are peroxisomes and what is their function?
Membrane bound organelles containing catalase to regulate hydrogen peroxide concentration and oxidases involved in beta-oxidation of fatty acids
What is the structure of mitochondria?
Permeable outer membrane containing porin
Folded inner membrane- cristae
Filled with amorphous matrix
What is the function of the mitochondria?
Powerhouse of the cell
What are the components of the cytoskeleton?
Microfilaments- fine strands of actin
Microtubules- Larger than microtubules
What is the role of the cytoskeleton?
Provide strength and support
Allow for cell motility
What is a hydrogen bond?
Electrostatic attraction between polar groups when H is bound to O, N or F
What defines a molecule’s water solubility?
Polarity
Define the term amphipathic
A molecule containing both hydrophobic and hydrophilic parts
Give an example of an amphipathic molecule
Phospholipids- hydrophilic heads, hydrophobic tails
How do amphipathic molecules act in water?
Minimise disruption by forming bilayers or micelles
How can pH be calculated?
pH=-log[H=]
pH=pKa=log[A-]/[HA]
What are buffers?
Solutions of weak acids and their salt
How do buffer solutions work?
If OH- is added, it combines with free H+ to form H2O
If H+ is added, it combines with OH- to form H2O
These ions are then replaced by the dissociation of acid and water and the pH remains constant
Describe the basic structure of a cell membrane
Phospholipid bilayer containing proteins
List the classes of membrane proteins
Integral membrane proteins
Peripheral proteins
What are integral membrane proteins?
Amphipathic proteins that cannot be removed without disrupting the membrane
What are the types of integral membrane protein and their functions?
Channels, through which ions can cross
Carriers, to transport substances across membranes
Enzymes, with binding sites
Receptors, recognition sites
What are peripheral proteins?
Non-amphipathic proteins that can be removed without major disruption to the membrane
What function do peripheral proteins have?
Usually enzymatic
Important for cell shape and motility
What is the protein content of different cell membranes?
Schwann cells= 18%
Normal= 50%
Mitochondria= 75%
What factors aid diffusion?
Large surface area
High permeability
High concentration gradient
What must molecules be to diffuse through the membrane?
Small
Uncharged
Hydrophobic
What are the different types of channel proteins?
Open channels
Gated channels- ligand or voltage gated
How do voltage gated channels work?
Changes in the electrical potential act on charged regions of channel proteins, changing their conformation, opening or closing the channel
How do ligand gated channel proteins work?
When a certain chemical binds to a channel protein, it produces a change in conformation, and opens or closes the channel
What is the electrochemical gradient?
The difference in charge between two compartments
What charge is carried by the inside of the cell?
-70mV
What are carrier mediated transport systems?
Proteins with binding sites for a substance, that changes conformation upon binding, allowing the molecule to diffuse into the cell, and allowing the protein to return to its original shape
What are the types of carrier mediated transport systems?
Facilitated diffusion
Active transport
What is active transport?
Transport against a concentration gradient, requiring energy from ATP
Define osmolarity
Concentration of a solution, expressed as the total number of osmoles per litre
Define tonicity
Concentration of non penetrating solutes on the two sides of the membrane
What are the 3 types of solutions that can occur in the body?
Isotonic
Hypotonic
Hypertonic
What are isotonic solutions?
Equal number of non-penetrating cells on either side of the membrane
What are hypotonic solutions?
Solutions where the concentration of non-penetrating particles are higher inside the cell than outside
What are hypertonic solutions?
Solutions where the concentration of non-penetrating cells is higher outside the cell than inside
Explain the movement of water in and out of the cell in hyper and hypotonic solutions
Hypotonic= water moves into cell Hypertonic= water moves out of cell
Describe the process of endocytosis
Invagination of the membrane to form a vesicle around the target substance, which eventually separates from the membrane on the cytoplasmic side and migrates into the cell
Describe the process of exocytosis
Invagination of the membrane around the target substance from the cytoplasmic side, which opens out into the extracellular space
What is epithelial tissue?
Tissue that covers surfaces and separates compartments
What are cell-cell junctions?
Junctions created between epithelial cells providing cell anchorage, sealing intracellular spaces and allowing for cell-cell communication
What are desmosomes?
Adhering junctions proving firm anchorage
What are tight junctions and what is their function?
Joining of membrane between two cells, forming a virtually impermeable barrier, sealing sections
What are gap junctions and what are their functions?
Connection between cytoplasm of two cells, allowing for cell-cell communication
What are cell-extracellular matrix junctions called?
Hemidesmosomes
What is the function of hemidesmosomes?
Anchor cells
What are the types of epithelial cells?
Squamous
Cuboidal
Columnar
What is the structure and function of simple squamous cells?
Thin, single cell, allows for easy diffusion
What is the function of simple cuboidal cells?
Secrete, absorption, pumping
What si the function of ciliated columnar cells?
Move mucus
What is the structure of stratified squamous epithelial cells?
Multiple layers, thick, layers can be sloughed off to allow for new growth
What is the function of stratified cuboidal cells?
Protection
What is the function of stratified columnar cells?
Protection and secretion
What epithelial cells are in the liver?
Hepatocytes
What functions do hepatocytes have?
Secretion
Line blood vessels and bile ducts
How are cells arranged in the kidneys?
Arranged into nephrons
What are the functions of the kidney nephrons?
Filtration of blood, partial absorption of filtrate
What do epithelial cells line in the kidney?
Blood vessels and the renal pelvis
What are glands?
Collections of multi or single celleular secretory epithelial cells
What are the 2 types of glands and where do they secrete into?
Endocrine- secrete into bloodstream
Exocrine- secrete onto surface i.e. sweat
What are the different gland structures?
Simple- tubular, acinar
Compound- tubuloacinar
What kind of secretions does each gland type secrete?
Tubular= thin, watery Acinar= thicker, mucousal
What are the consequences of abnormal glandular function?
Overproduction= pituitary giantism Underproduction= pituitary dwarfism
What is the extracellular matrix comprised of?
Fibres
Ground substance
Tissue fluid
What kind of fibres are present in the extracellular matrix?
Collagen fibres
What are the differences between collagen and elastic fibres?
Collagen is flexible bit inelastic
Elastic fibres are very elastic
What is group substance composed of?
Proteoglycans
Glycoproteins
Hyaluronic acid
Water
What are the three layers of the skin?
Epidermis
Dermis
Hypodermis
What are the 5 layers of the epidermis?
Stratum basale Stratum spinosum Stratum gramulosum Stratum lucidium Stratum corneum
How does the stratum basale bind?
To the basement membrane via hemidesmosomes
To other cells via desmosomes
How is the stream granulosum defines?
Presence of keratohyalin granules
What is the turnover rate of the strum corneum?
30 days
What 2 layers is the dermis composed of?
Papillary layer
Reticular layer
What is the papillary layer of the dermis composed of?
Loose connective tissue
Blood vessels
Nerve endings
What is the reticular layer of the dermis composed of?
Sense irregular connective tissue
Collagen bundles
Elastic fibres
What is the interface between the dermis and epidermis like?
Irregular
What are the functions of bone?
Mechanical support and attachment for muscles, tendons, ligaments and joints
Protects internal organs
Mineral reservoir
Support blood formation
Describe the process of endochondral ossification
Bone forms as cartilage first
Blood vessels and osteogenic cells invade the cartilage framework
Cartilage remains as growth plates until 18-21 years old
Describe the process of intramembranous ossification
Bone forms as a fibrous plate
Bone cells differentiate from fibroblasts and haematopoietic precursors
What is the composition of bone?
20% water
35% proteins- collagen type 1, growth factor proteins, other matrix proteins
Minerals
What are the 3 areas of long bone and where are they found?
Epiphyses- end of a bone
Metaphyses- between the two
Diaphyses- shaft of bone
What is the epiphyses of long bone made up of and why?
Trabecular (spongey) bone
Act as a softer interface at joints
What is the diaphyses of bone composed of?
Cortical bone