Week 1 Flashcards
Where is extracellular fluid?
Outside the cell
What is it called when pH is too low?
Acidosis
When is MRI used?
For soft tissue. MRI is the gold standard for soft tissue imaging
What are the levels of organization in an organism?
- Atom
- Molecule
- Macromolecule
- Organelle
- Cell
- Tissue
- Organ
- Organ system
- Organelle
What are the four levels of protein organisation?
- Primary
- Secondary
- Tertiary
- Quaternary
Proximal
Closer to the axial body along an appendage
Pathogenesis of Rickets
- Insufficient/no vitamin D3, meaning osteoclasts have the sole responsibility of maintaining calcium levels.
- Bone breakdown increases
- Decreased bone density -> rickets
What are the consequences of too much glucose in the bloodstream?
Glucotoxicity: osmotic gradient draws water out of cells, causing dehydration and death of cells.
Why are carbohydrates the primary source of energy for the body?
They can be rapidly and easily converted into energy for use.
Why is ultrasound not used when air and calcification are involved?
Air and calcified structures reflect sound strongly, creating a hyperechogenic line that obscures structures deep to it
Mid-sagittal plane
Divides the body into equal left and right halves
Describe blood pressure homeostatic regulation
Blood pressure changes -> baroreceptors detect -> sent via afferent neurons to brainstem -> information sent along efferent nerves cause heart rate to adjust
What type of feedback is involved in homeostatic regulation?
Negative
Why are pregnant women and children at higher risk from ionising radiation?
The effects of ionising radiation unfold over time. Since unborn (and born) children have more of their lives ahead of them, they are at higher risk of experiencing adverse effects from this exposure.
Advantages of MRI
- No ionising radiation exposure
- Very high image quality
Rostral
Superior-anterior tip
What is a polypeptide with less than 50 amino acids called?
Peptide
Define Regional anatomy
Study of features in a specific anatomical region
State the basic feedback loop of homeostatic regulation
Stimulus -> receptor -> control center -> effector -> response -> homeostasis
Describe the quaternary level of protein organisation
Multiple 3D polypeptide joined together
Why does it make sense that IV contrast could cause acute renal failure?
The kidneys are reponsible for filtering IV contrast out of the blood. Therefore, kidneys are closely related to the processing of IV contrast, and any negative effects of the substance could act upon the kidneys.
What does physiology pertain to?
The function of body parts
What elements are in carbohydrates?
Carbon, Hydrogen and Oxygen (think: glucose) About 1:2:1 ratio
Describe how the body increases calcium levels
- Calcium decreases
- Parathyroid cells detect this change
- This increases the cell’s secretion of Parathyroid Hormone (PTH)
- PTH acts on bone, kidney and gut cells.
> Osteoclasts break down bone to get calcium
With the help of the steroid hormone vitamin D3:
> More calcium is digested from food
> More calcium is reabsorbed into blood
Define cytology
The study of cells (cyto-plasm)
Para-sagittal plane
Divides the body into unequal left and right halves
Why is endocrine signalling slower than nervous signalling?
Endocrine communication requires molecules to flow through the bloodstream to target sites, which is much slower than the electrical impulses used in nervous signalling
What are two kinds of extracellular fluid?
Interstitial: Between cells and vessels
Intravascular: Within vessels
What does physiology pertain to?
The function of body parts
How does CT differ from x-rays?
CT scans involve taking multiple images from varying angles, which are then reconstructed into multi-slice sections that can be reformatted into multiple planes
What are the disadvantages of x-ray?
- Radiation exposure
- Limited detail of images
- Static image
List some factors that are homeostatically regulated
- Blood pressure
- Blood pH
- Blood glucose
- Blood volume
- Core body temp (not peripheral)
List some physiological responses that occur when core body temperature is too low
- Shivering
- Lack of sweating
- Vasoconstriction (smooth muscles contract; less flow to superficial arterioles)
- Increased brown fat metabolism (therefore increased heat generation)
- Piloerection (leads to goosebumps)
Where is the appendicular body?
Appendages and girdles (e.g. connections to the axial body)
True or false: homeostasis always tends toward the same internal conditions
False. Homeostasis is a dynamic steady state, meaning it can adapt to determine the ideal environment for the body depending on external stimuli
What is the natural pH of the human body?
7.4
Where is intracellular fluid?
Inside the cell
When is CT used?
- Diagnostic tool
- Ongoing monitoring in oncology
- Preoperative planning
- When detail of lung, bone, and soft tissue is needed
What are the advantages of computed tomography scans?
- Relatively accessible
- Relatively cheap
What are the risks of x-rays?
Ionising radiation associated with increased cancer risk (lower exposure than CT)
Posterior (dorsal)
The “back” surface of the body
What is the basic definition of lipids?
Organic molecules that cannot readily dissolve in water
Distal
Further from the axial body along an appendage
What fluid-balancing hormone is made in the hypothalamus? What are its names?
- ADH
- Vasopressin
What elements are in lipids (+ ratio)
Carbon, hydrogen and oxygen, at about ~1:2:<1
Define embyrology
The science of the development of the embryo from fertilization to the foetal stage
Structure and function of the lymphatic system
Structure: lymph, lymph vessels and lymph organs
Function: Fluid balance, defense and immunity
Caudal
Inferior-posterior tip
What are the three types of RNA and their functions?
- mRNA: formed during transcription during protein synthesis
- tRNA: has corresponding anticodons to mRNA that deliver amino acids to ribosome
- rRNA: structural unit of ribosomes
Disadvantages of MRI
- Claustrophobia
- Limited accessibility (expensive, immobile, large machines)
- Loud
Is access to nuclear medicine limited or abundant?
Limited
What are the three levels of organisation of matter?
- Atoms
- Elements
- Compounds
What are the risks of CT scans?
Ionising radiation exposure
Transverse plane
Divides the body into superior and inferior components
How does MRI work?
- Body is placed in magnetic field that aligns all the protons in the body
- Radio waves are projected through the body, disturbing proton alignment
- Protons return to alignment differently according to various tissues
- Therefore, proton alignment can be processed into an image
What is positive feedback?
Any feedback loop that amplifies an initial stimulus (e.g. blood clotting -> platelet coagulation)
Is body fat proportional or inversely proportional to water content? Why does this make sense?
Inversely proportional. Lipids are insoluble in water.
Blood pressure/volume regulation (too high)
Detected -> stimulate Atrial Natriuretic Peptide -> inhibits aldosterone production -> less water and salt are reabsorbed, decreasing BP and volume back to regular levels
Anterior (ventral)
Closer to the “front” surface of the body
Why is thermoregulation important?
Critical enzymes in the body will become inactive or denatured if allowed outside of a narrow temperature range, thus impairing bodily functions.
What are the four kinds of cellular signalling used in homeostasis?
- Juxtacrine: Between two touching cells
- Paracrine: Between two cells that are separated by a short distance
- Endocrine: Where a message is relayed through vessels from one cell to another
- Autocrine: A cell sends a message to itself
True of false: the same IV contrast is used in CT and MRI?
False
Which imaging techniques involve the use of ionising radiation?
CT and X-ray
Where are osmoreceptors located?
The hypothalamus
Why can hypoglycemia cause neural dysfunction?
- CNS and PNS almost exclusively use glucose for cellular respiration
- Therefore, when less glucose is present, neurons have insufficient energy, and so neural dysfunction occurs
What is the main function of carbohydrates?
Primary source of energy for the body
Pathogenesis of Type 2 Diabetes
- Body develops a resistance to insulin
- Blood sugar levels cannot be monitored as easily
What are the risks of MRI?
- Metal cannot be in the body
- Risk in pregnancy
- IV contrast can be used
Inferior
Closer to the plantar surface of the foot
Define systematic anatomy
The study of structures that make up an organ system
Structure and function of the cardiovascular system
Structure: Blood, blood vessels, heart
Function: Transport and exchange of nutrients, waste, and gases around the body
Describe the tertiary level of protein organisation
3D polypeptide structure
What is homeostasis?
Homeostasis is the self-regulatory process of the maintaining stable internal conditions within the body such that cells, tissues and organs can function optimally.
What is negative feedback?
Any feedback loop that negates an initial stimulus (e.g. thermoregulation)
Define anatomical pathology
Study of the structural changes that are brought about as a result of (and during) disease
Structure and function of the integumentary system
Structure: Skin and accessory structures
Function: Sense and protect. Unique in its exposure to the external environment
Why do carbohydrates only contribute to ~2% of the body’s mass?
They are the body’s primary energy source, and are burned quickly, meaning most of their mass is converted to energy relatively quickly
What are the risks of IV contrast?
- Potential allergic reaction
- Possible acute renal failure
When are X-rays used?
- Dense structures such as bones (things with calcification)
- When tissues of differing density are present
What are the three classifications of carbohydrates?
Monosaccharide: One saccharide ring
Disaccharide: Two saccharide rings
Polysaccharide: More than two saccharide rings
Describe the primary level of protein organisation
Sequence of amino acids joined by peptide/amide bonds
What are some consequences of diabetes
- Cardiovascular disease
- Liver disease
- Nervous damage
Draw the basic structure of an amino acid
- Central carbon
- Hydrogen
- R Group
- Carboxy group
- Amine group
Why is IV contrast used in CT scans
To assess the vascularity of structures
Structure and function of the musculoskeletal system
Structure: muscles, bones, and joints
Function: Mechanical protection, support, movement
What is unique about carbon atoms in terms of biomolecules?
Carbon atoms can form covalent bonds with four other atoms, enabling them to create a wide variety of molecules of all shapes and sizes
Methods of body fluid movement (with corresponding pressures)
Hydrostatic > Osmotic: Filtration
Hydrostatic < Osmotic: Reabsorption
Superior
Closer to the top of the head
What are some important functions of calcium in the body?
- Necessary for muscle contraction
- Bone density
- Neurotransmitter release
Coronal plane
Divides the body into anterior and posterior components
Are any groups more at risk from ionising radiation?
Pregnant women and children
Define Surface/Superficial Anatomy
Study of anatomical features on the surface of the body (think: deep, intermediate, superficial)
What is a polypeptide with more than 50 amino acids called?
Protein
Classifications of fluids
Solutions: clear, particles stay in solution
Colloids: Larger molecules remain dispersed but are not chemically combined
Suspensions: Large particles that eventually precipitate out of solution
Structure and function of the nervous system
Structure: CNS (brain and spinal cord) and PNS (all other neurons outside these areas)
Function: Detect external stimuli, integrate sensory input, issue corresponding responses and coordinate the involvement of other body systems in homeostatic regulation
What is CT not good at imaging?
Soft tissue structures of similar density
What are the four types of macromolecules?
- Proteins
- Carbohydrates
- Lipids
- Nucleic Acids
Disadvantages of ultrasound
- Limited range of depths and tissues can be tested
- Some scans benefit from patient cooperation
Define comparative anatomy
The comparison of anatomical features between species
Blood pressure/volume regulation (too high)
Detected -> stimulate Atrial Natriuretic Peptide -> inhibits aldosterone production -> less water and salt are reabsorbed, decreasing BP and volume back to regular levels
What is nuclear medicine?
Using radioisotopes to assess function, diagnose and treat disease
Describe the secondary level of protein organisation
Alpha helices and beta sheets. Held together by hydrogen bonds between amide bonds
Where is the axial body?
Anything connected to the midline (trunk, head, torso, neck)
Blood glucose feedback loop (too low)
- Blood glucose decreases
- Beta cells in pancreas detect
- Alpha cells in pancreas secrete glucagon
- Glucagon prompts glycogen breakdown in liver cells
- Blood glucose increases
Composition of blood
Plasma: 55%
Buffy Coat
Formed Elements: 45% (leukocytes, erythrocytes, platelets)
What is the function of nucleic acids
To store and transfer information
Radiographic anatomy
Study of the anatomical structures of the body using radiographic films (e.g. x-rays, CT, MRI)
What are the advantages of x-ray?
- Quick
- Cheap
- Accessible/mobile
What proportion of body fluids are intracellular and extracellular?
Intra: 66%
Extra: 33%
What are the two kinds of feedback?
Positive and negative
What is pathology
The study of structural and functional changes that occur in an organism due to (or during) disease
What is biology?
The study of life
Structure and function of the urinary system
Structure: kidneys, ureters, bladder, urethra
Function: Fluid balance and waste excretion
Pathogenesis of Type 1 Diabetes
- Body develops antibodies to attack beta cells in pancreas
- Insulin secretion is impaired
- Blood glucose level cannot be regulated as well as normally
What is the basic mechanism of ultrasound?
A transducer emits a sound wave and records the echo, which is processed into a 2D image (since various tissues reflect sound differently)
Advantages of ultrasound
- No ionising radiation
- Dynamic imaging
- Cheap
- Quick
- Mobile/accessible
What are the two types of nucleic acids?
RNA (ribonucleic acid) and DNA (Deoxyribonucleic acid)
Define histology
Study of the organization and details of biological tissues
ADH/Vasopressin Mechanism
Increase in plasma osmolality/decrease in blood pressure -> vasopressin travels from hypothalamus along nerves to pituitary and enters circulation -> vasopressin receptors are activated in the kidneys -> water reabsorption increases as aquaporins are added to collecting ducts in the nephron
Define microanatomy
Study of anatomical structures on a microscopic scale
How many types of amino acid are there?
20
Blood pressure/volume regulation (too low)
Blood pressure decreases -> kidneys detect this, and increase renin production -> this indirectly increases angiotensin II production -> this indirectly increases aldosterone production in the adrenal cortex -> more sodium is reabsorbed -> water follows to increase blood pressure & volume [RAAS]
What is it called when pH is too high?
Alkalosis
What is the maximum safe dose of ionising radiation?
None. All doses of radiation must be justified!
Which two control systems regulate organ systems to maintain homeostasis?
- Nervous System
- Endocrine System
Structure and function of the reproductive system
Structure: Sex organs, cells, and tissues
Function: production of sex cells and hormones, and support of embryonic development
Blood glucose feedback loop (too high)
- Blood glucose increases (e.g. after eating)
- Beta cells in pancreas detect
- Beta cells secrete insulin
- Insulin prompts skeletal, liver and fat cells to take up more glucose, increases rate of respiration, and increases glycogen formation
- Blood glucose decreases
Disadvantages of CT scans?
- Far higher dose of ionising radiation than x-ray
- Bad at imaging soft tissue of similar density
- Patient needs to be stable enough to get to the radiology department (not mobile)
- Mostly static images
What elements are biomolecules made of?
Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorous (CHONP)
Structure and function of the digestive system
Structure: Gastrointestinal tract and accessory organs (liver, gall bladder, pancreas)
Function: Nutrient absorption and waste excretion
What are functional groups?
Groupings of atoms that influence the properties of an overall molecule
List some physiological responses that occur when core body temperature is too high
- Sweating
- Vasodilation: smooth muscles relax, increasing flow to superficial capillaries
- Hair follicles relax
Which elements do nucleic acids contain?
CHONP
What does anatomy pertain to?
The structure of body parts and their interaction to form a whole
What are some secondary functions of lipids in the body?
- Cell membrane (phospholipid bilayer)
- Chemical messengers
Name the process of maintaining a stable core temperature?
Thermoregulation
What are the risks of nuclear medicine?
Ionising radiation is inherent in the process
Define gross anatomy
Study of anatomical features that can be seen with the naked eye
Structure and function of the endocrine system
Structure: endocrine glands
Function: Work alongside the nervous system in the maintenance of homeostasis via various forms of chemical communication
How many cell types are there
~200
How many cells in the average human?
~30 trillion
What is the function of the nucleus?
Mastermind of the cell. Houses DNA.
What is in the chromatin of the nucleus?
DNA and histones
What is the nucleus surrounded by?
The nuclear envelope
What is the nuclear envelope continuous with?
The rough endoplasmic reticulum
What does the nucleus contain for the sake of communication?
Nuclear pores
What is a gene?
A section of DNA that codes for a protein
True or false: all DNA is made up of exclusively genes
False
What is the role of the nucleolus?
Produces rRNA
Why might a cell have multiple nuclei?
It may need to produce many types of proteins compared to a regular cell
There are four types of histone; what are their structural differences?
The variants wrap DNA with varying tightness and alter stability of chromosomes/nucleosomes
Word origin of “chromatin”
Greek word “chroma” meaning colour
How stained is euchromatin and what does it signify?
Lightly stained, signifies active cell
How stained is heterochromatin and what does it signify?
Highly stained, signifies inactive cell
What is the difference between cytosol and cytoplasm
Cytosol: fluid in cell (intracellular)
Cytoplasm: contents of cell (including non-fluid)
What are the two subunits of ribosomes
- Large subunit
- Small subunit
Both made of rRNA and protein
What is the function of ribosomes?
Produce proteins
Which endoplasmic reticulum do ribosomes attach to?
Rough ER
What is the function of free ribosomes?
To make proteins that are used in the cell
What is the role of the endoplasmic reticulum?
To fold proteins into their 3D polypeptide shape
What is the role of the smooth endoplasmic reticulum?
To produce fatty acids and steroid hormones (+ detoxification)
Where might the smooth ER be abundant?
Liver (detoxification)
Which organelle transports newly-folded proteins from the ER?
Golgi body
How do proteins get to the golgi body?
Transport vesicle -> fuses with entry phase of the golgi body
How do proteins exit the golgi body?
Through a secretory vesicle
How do proteins know where to be transported?
The golgi body “tags” them on their way through, giving them a location
What is the function of vacuoles?
Store water and waste materials
What are lysosomes?
- Garbage disposal of the cell
- Digest and break down toxic products (w/ specific enzymes)
What is the pH of lysosomes?
5
What is autophagy?
Lysosomes break down parts of their own cell that are malfunctioning, or when the body is starving.
What are mitochondria
Powerhouse of the cell. Site of aerobic respiration. Produces ATP
How do mitochondria affect gene expression?
They produce cofactors that enzymes use during gene expression. Therefore, mitochondrial inhibition can alter the gene expression of a cell.
What is the function of the cytoskeleton?
Provides strength, shape, flexibility and structural support to the cell
What is the cytoskeleton made of?
Filamentous proteins
What is the centrosome?
- Component of the cytoskeleton
- Organisation structure of microtubules
- Important in cell division (anaphase, pulling apart sister chromatids)
What are microvilli and where can they be found?
- Small protrusions that increase SA:V ratio
- Can be found in small intestine, to maximise rate of nutrient absorption
What are cilia and where can they be found?
- Small, hair-like extensions (longer than microvilli) that also maximise SA:V ratio
- Can be found in the bronchus where they filter mucus out of airways
What are flagella and where can they be found?
- Used primarily for cell mobility
- Can be found on sperm cells
What is the function of the cell membrane?
- Protects the contents of the cell
- Allows for communication with other cells (e.g. surface proteins)
- Maintains composition of cytoplasm and extracellular fluid
True or false: Gases can freely cross the cell membrane
True
In terms of polarity and size, what types of molecules can and cannot cross the cell membrane?
Large polar molecules cannot enter the cell, but lipids and small polar molecules (e.g. water) can. This makes sense in terms of chemistry.
