Overall Flashcards
Do cells have similar physiology in different anatomical locations?
Yes mostly but certain specialised cells are different
What does the nucleus in the cell of the human body contain?
The nuclear envelope with pores in, nucleoplasm, nucleolus and chromatin
What is the ph within a cell?
7.35
What are some of the organelles in the cell?
Nucleus, endoplasmic reticulum (smooth and rough), ribosome, cell membrane, golgi complex (apparatus), mitochondria, lysosomes, microfilaments and microtubules, vesicles
What does the cell membrane do?
Separates the internal part of the cell from the external environment, adds support for sensing receptors and allows active uptake and output of chemicals
What are lipids?
A diverse group of organic compounds including fats, oils, and hormones
What is the cell membrane made of?
A phospholipid bilayer
What is a phospholipid?
It is a lipid with a hydrophilic head containing a phosphate group and 2 hydrophobic tails made from fatty acids
What does the nucleus do?
It has most of the DNA in it (nuclear DNA), handles copying of DNA to allow protein synthesis and performs cell replication
What does the endoplasmic reticulum do?
It synthesizes lipids (smooth ER) and proteins (rough ER)
What does the Golgi apparatus do?
It organises the trafficking of proteins and lipids to the external environment
What do mitochondria do?
They generate most of the chemical energy for a cell by turning the glucose we eat and turning it into energy, which is stored in ATP
Do mitochondria have any DNA?
Yes, it is different from nuclear DNA because it comes only from the maternal line
What is adenosine triphosphate (ATP)?
It is an energy-carrying molecule (a nucleotide) found in all living cells and releases the energy to fuel other cellular processes
What do microtubules and microfilaments do?
They provide structural support (like scaffolding) and they carry molecules throughout the cells (motor proteins like kinesin and dynein)
How do cells sense their environment?
The surface receptors in the cell membrane sends a signal to inside the cell and makes a chemical cascade, which triggers a response
What is differentiation with respect to cells?
How cells change from one cell type to another cell type
What is the anatomical position based on?
Leonardo Da Vinci’s anatomical man
What is the features of the anatomical position (also known as the upright reference position)?
Erect (standing up),arms by the side, thumbs outwards (palms facing forward), eyes straight ahead, straight back, straight limbs
What are the 4 main gross anatomical positions?
Supine (on back), prone (on front), right lateral recumbent (on right side), left lateral recumbent
What is the mid-line of the human body?
A line that splits your body from your left and right halves
What do the medial and lateral descriptors mean?
Medial = towards the mid-line, lateral = away from the mid-line
Does a medial view/aspect of a foot (for example) show the inside or outside of the foot?
Inside
What do the superior and inferior descriptors mean?
Superior = above an arbitrary point, inferior = below an inferior point
What does anterior and posterior mean and what are the other names of them?
Anterior means front, also known as ventral. Posterior means back, also known as dorsal
What do the distal and proximal descriptors mean?
Distal = away from the main body, proximal = towards the main body
What do the dexter and sinister descriptors mean?
Dexter = right side, sinister = left side
What is the coronal plane?
Vertical plane that divides the body into anterior and posterior sections
What is the sagittal plane?
Vertical plane that divides the body into left and right sections (symmetrical if along the mid-line)
What is the transverse plane?
Horizontal plane that divides the body into superior and inferior parts
What 4 main groups can we divide the body into?
Head and neck, upper limb, lower limb, torso/trunk (thorax, abdomen and pelvis)
What is flexion?
Decreasing the angle between two ventral surfaces
What is the flexion and extension of the upper segment of the upper limb?
Moving the whole arm forward or backwards (note: upper segment refers to shoulder flexion and extension, not at the elbow)
What is the abduction or adduction of the upper segment of the upper limb?
Away from the mid-line or towards the mid-line
What is pronation and supination of the lower segment of the upper limb?
Pronation is when the palm is face down, whilst supination is when the palm is face up
What is thumb opposition?
The thumb pad can touch the pad of the middle finger (only primates and possums can do this)
What is circumduction?
A circular movement of a limb or extremity
What is the flexion and extension of the wrist?
Flexion is when the palm moves towards the forearm (ventral surfaces coming together) and extension is when the dorsal surfaces move towards each other
Is the radius the outer or inner bone of the arm? (palms forward)
Outer
Lateral and medial deviation of the wrist is also known as what and why?
Radial (lateral) and ulnar (medial) because these are the bones the hand moves towards when doing these movements
What is the flexion and extension of the hip?
Flexion is when the leg is brought in front of the body and extension is when the leg is brought behind the body
What is the adduction and abduction of the hip?
Adduction moves the leg towards the mid-line of the body, whilst abduction moves the leg away from the mid-line of the body
What is the lateral and medial rotation of the hip?
Rotating the hip either away from the body and towards and the foot points either outwards (lateral) or inwards (medial)
Do the knees only have flexion-extension motion?
No they have slight rotation for stability and they are hyperextend when standing straight
What is the inversion and eversion of the ankle?
Inversion is when the foot rotates so that the sole towards the midline of the body and eversion is when the foot rotates away from the midline of the body
What is dorsi-flexion and plantar-flexion?
Dorsi-flexion is ankle flexion and plantar-flexion is ankle extension
Instead of thinking of individual muscles, how can we think of them to simplify things for flexion and extension purposes and what is an example?
In compartments so the anterior compartment of the upper arm would include the biceps for example
What does the central nervous system (CNS) consist of and is it encased in bone?
The brain and spinal cord and yes it is
What does the peripheral nervous system consist of and is it encased in bone?
Peripheral nerves, ganglia and no
What are afferent nerves?
Messenger neurons that carry information from sensory receptors to the central nervous system
What are the efferent nerves?
Motor neurons that carry signals from the brain to the peripheral nervous system
What are the 2 parts of the peripheral nervous system?
Autonomic and somatic nervous system
What is the somatic nervous system?
It consists of nerves that go to the skin and muscles and is involved in conscious activities (purposes of moto function and sensation)
What is the autonomic nervous system?
It consists of nerves that connect the CNS to the visceral organs. It mediates unconscious activities (coordinates the internal environment - homeostasis)
What is the enteric nervous system?
The network of nerves that innervate (supply nerves to) the gun and coordinate gut function
What is the vascular nervous system?
The network of nerves that innervate (supply blood to) the blood vessels and coordinate vascular smooth muscle functions
Do nerves run anatomically close to blood vessels?
Yes (capillaries run through nerves)
What does the speed of the electrical signal through the neurons depend on?
The axon diameter and the amount of myelin sheath there is
What do neurons (nerve cells) do?
Transmit electrical signals
What are the main parts of a nerve cell?
Cell body = soma (includes nucleus), dendrites, axon, myelin sheath and terminal branches of axon
What do dendrites do?
The receive messages from other cells
What do axons do? (also known as nerve fibres)
They pass messages (electrical/neural impulses) away from the cell body to other neurons, muscles or glands
What is the myelin sheath?
Myelin insulates some axons and increases the speed of the electrical impulses
What are the 4 parts of the spine?
Cervical, thoracic, lumbar, sacrum (coccyx at the bottom)
How does a neuron send a message to another neuron?
It sends an electrical signal down its axon and at the end of the axon, it changes into a chemical signal. The axon releases the chemical signal with neurotransmitters (chemical messengers) into the synapse to a neighbouring dendrite, which converts the chemical signal back into an electrical signal.
What is a synapse?
The space between the end of an axon and the tip of a dendrite from another neuron
How many vertebrae are there for the cervical, thoracic and lumbar spine?
7 for cervical, 12 for thoracic and 5 for lumbar
What does the spine/vertebral column consist of?
Vertebrae separated by intervertebral discs and the vertebral column surrounds the spinal cord, which travels within the spinal canal, formed from a central hole behind each vertebra.
What is the structure of the sacrum and coccyx?
The vertebrae are fused and there are 5 in the sacrum and 4 in the coccyx
What are the main 2 parts of the autonomic nervous system? (enteric is sometimes considered as part of this too)
Sympathetic and parasympathetic nervous systems
What is the sympathetic nervous system responsible for and where in the body is the origin of this system?
Fight or flight response. In the thoracolumbar division
What is the parasympathetic nervous system responsible for and it is also known as what type of outflow?
Rest and digest. Craniosacral
What is a ganglion?
A group of neuron cell bodies
What is the resting membrane voltage and what value does it have?
The potential difference between the inside and outside of the plasma membrane of the axon in a neuron and -70 mV
What is a nerve impulse?
An electrochemical event that occurs in nerve cells following proper stimulation
Is a nerve impulse a building process or an all-or-nothing process?
All-or-nothing
What is the voltage curve that characterises a nerve impulse called?
An action potential
What makes a cell be classed as an excitable cell?
Action potentials need to occur
What does a sodium-potassium pump do in terms of excitable cells (like neurons) and how?
It maintains the resting potential by ensuring there are low levels of sodium ions and high levels of potassium ions by moving 3 sodium ions out with 2 potassium ions in (net loss of one)
What is the Nernst potential?
The potential difference across a cell membrane that exactly opposes net diffusion of a particular ion through the membrane
What is the Nernst equation?
The voltage balancing out the unequal ion concentration across the membrane (the equilibrium potential for that ion, eg potassium, where there is no net movement of the ion across the membrane)
What makes the resting potential negative?
More cations are leaving the cell than entering
What 3 things are required for action potential generation?
A polarised membrane (charge separation), sodium and potassium voltage-gated channels for discharging the polarisation and a stimulus for activating the voltage-gated channels
In an action potential, what voltage-gated ion channels are open on the rise of the potential until the top of the action potential?
Sodium channels, which open and sodium ions go into the cell and then more open after the threshold limit is reached
In an action potential, what voltage-gated ion channels open after the top point and until when?
The potassium channels are open and then stop when the potential is just below the resting potential, and then the potential slightly rises to the resting potential action
In an action potential, what does opening the sodium channels do?
Sodium ions will go into the cell as there is a concentration gradient there, which increases the positivity of the cell membrane potential and causes depolarisation
During depolarisation in an action potential, what value does the membrane potential reach at the top?
+30 mV
At the the top of an action potential, when the sodium channels close and potassium channels open, what does this do?
Potassium ions will leave the cell as there is a concentration gradient there and repolarisation occurs back to -70 mV
What is the threshold voltage for an action potential to occur?
-55 mV
What does depolarised mean for a neuron in an action potential?
The cell membrane is positive inside and its negative outside
When does hyperpolarisation occur in an action potential and what is it?
After repolarisation when voltage-gated potassium ions have been opened but there are more potassium ions outside than there are sodium ions inside, which causes the membrane potential to drop slightly lower than the resting potential
What is the refractory period after an action potential?
Potassium ions return inside the membrane and the sodium ions move outside, and the neuron doesn’t respond to any other stimuli
What is the cardiac action potential?
The membrane potential of the cardiac myocytes that signifies electrical activity of the cell
What initiates the cardiac action potentials?
Specialised pacemaker cells (in the sinoatrial node in the right atrium)
How many phases are there in the cardiac action potential?
5, Phases 0-4
What is phase 0, 1 and 2 for cardiac action potentials?
Phase 0: depolarisation, where sodium ions rapidly enter into the cell and calcium ions slowly enter the cell
Phase 1: sodium ion channels close
Phase 2: plateau phase, where potassium ions move rapidly out of the cell and calcium ions move slowly into cell
What is phase 3 and 4 for cardiac action potentials?
Phase 3: rapid repolarisation where calcium channels close and potassium ions move rapidly out of the cell
Phase 4: resting potential where there are leaky potassium channels
What phases have the long absolute refractory period in cardiac muscle cells and what is it?
Phase 0 to 3 and it means no second cardiac action potential can be initiated
How is the myelin sheath around some of the axons of neurons made in the PNS?
Myelinating Schwann cells that have wrapped around axons (Schwann cells can be myelinating or nonmyelinating)
What occurs at the points of the axon where the sheath of one Schwann cell meets the next (myelin sheath) and what are these gaps called?
The axon is unprotected and it is where the voltage-gated sodium channels are and Nodes of Ranvier
How do action potentials conduct along an axon?
Inrush of sodium ions at one node, which depolarises to reach the threshold of the next node and the action potential jumps from one node to the next (saltatory conduction)
How was the action potential first measured?
Intracellular recording by inserting a glass pipette into a cell and recording the potential changes wrt a reference electrode
What is extracellular recording for measuring action potentials?
One electrode placed in close proximity to the excitable cell and the reference electrode in the extracellular fluid to record potential changes at the membrane surface
What is patch clamping for measuring action potentials?
A suction is applied to form a seal to electrically isolate the membrane patch and all ions fluxing the membrane patch will flow into the pipette to be recorded
What are the main measurements of nerve conduction studies (NCS)?
Conduction velocity and amplitude
What are the two types of abnormality detected by nerve conduction studies?
Slowing due to demyelination and reduction in amplitude of response due to loss of axons
Abnormalities found from nerve conduction studies can have different patterns of peripheral nerve involvement, what are the three patterns?
Focal (single nerve affected), multifocal (if named nerves are affected, mononeuritis multiplex but if not, multifocal neuropathy) and generalised neuropathy
What disorders are related to nerve abnormalities? (can be found with nerve conduction studies)
Guillain-Barre syndrome (immune system attack part of the PNS), carpal tunnel syndrome (median nerve in forearm becomes pressed at the wrist by enlarged tendons/ligaments) and sciatic nerve problems (typically ruptured or bulging spinal disc pressing against roots of the nerve)
What is intra-operative spinal monitoring?
Functionally assesses nervous system integrity during surgical procedures involving spinal manipulation, like correcting scoliosis
What does a electroencephalography (EEG) measure?
It measures voltages fluctuations which result from ionic current flows within the neurons of the brain (brains electrical activity over a short time period around 30 mins)
What are EEGs used for (applications)?
Main diagnostic tool for epilepsy, used in comas and suspected brain death
How are conventional EEG recordings done?
8-16 leads placed on the scalp (10:20 configuration) over specific cortical areas
What does a normal EEG look like in the awake and alert state?
Irregular, low-voltage waves of high frequency
What types of waves are recorded on an EEG?
Alpha, beta, theta and delta waves
What are alpha waves and their frequency?
Present when awake with eyes closed (relaxed wakefulness), from occipital lobe, frequency is moderate (8-13 Hz)
What are beta waves and their frequency?
Associated with alertness, frequency is fast (13-30 Hz)
What are theta waves and their frequency?
Usually in sleep, frequency is slow (4-8 Hz)
What are delta waves and their frequency?
Seen in deep sleep, the largest amplitude of all ways and slow frequency (4 Hz)
What are foramen Ovale recordings?
Electrodes inserted into the opening in the skull (foramen ovale) to record electrical activity in the temporal lobe where seizures often arise
What are evoked potentials?
Recordings of electrical signals produced naturally by the brain following stimulation
What is a visual evoked potential (VEP)?
Electrophysiological signals in the brain evoked from visual simulations to determine the integrity of the visual system (eg optic nerve)
What is the auditory brainstem response (ABR)?
Auditory stimulation that generates neural activity along the central auditory pathway that can be detected by the brainstem
What does the auditory system comprise of?
Cochlea, cochlea nerve and the central auditory pathway, which extends from the nucleus of the cochlea to the primary auditory cortex (in the temporal lobe)
How can the auditory brainstem response (ABR) be recorded?
Temporal surface electrodes and analysed to determine whether sound transduction is within normal limits
How big is the heart approximately?
13cm long and 9cm wide, 200-425 grams
How much blood does each of the four chambers hold up to?
70 ml
What are the upper and lower chambers of the heart called?
Upper chambers called atria and lower chambers are ventricles
What veins go into the right atrium of the heart?
The superior and inferior vena cava
What is the valve name between the right atrium and the right ventricle?
Tricuspid valve
What is the valve name between the right ventricle and the pulmonary artery?
Pulmonary valve
What is the name of the veins going from the lungs to the left atrium?
Pulmonary veins
What is the name of the valve between the left atrium and the left ventricle?
Mitral valve
What is the valve name between the left ventricle and the aorta that goes to the rest of the body?
Aortic valve
Which chamber in the heart is the largest and strongest?
Left ventricle
How many times does the heart beat per day and how many litres is this?
100,000 times and 7,600 litres
What is the outer layer of the wall of the heat called and what is it composed of?
The epicardium and it is connective tissue covered by epithelium
What does the epithelial tissue on the epicardium do for the heart?
It is a barrier and protects the myocardium
What is the myocardium and what is it made of?
The muscular middle layer of the heart and it is spontaneously contracting cardiac muscle fibres
What are the three layers of the wall of the heart called from inner to outer layers?
Endocardium, myocardium and epicardium
What is the inner layer of the heart called and what does it consist of?
Endocardium and it is epithelial tissue and connective tissue
With respect to the exterior of the heart muscle fibres, are the interiors negatively or positively charged?
Negatively charged
What is the ‘natural pacemaker’ of the heart and where is it?
SA (Sinoatrial) node in the right atrium
What does diastole represent?
Ventricular filling and contraction of the atria driving blood into the ventricles and the SA node discharges
What does systole represent?
Ventricular contraction after the ventricles are full of blood and electrical signals are sent from the AV node (SA node recharges)
Which heart valves are open and closed during diastole?
Open: tricuspid and mitral valves
Closed: pulmonary and aortic valves
Which heart valves are open and closed during systole?
Open: pulmonary and aortic valves
Closed: tricuspid and mitral valves
How are the cross striations of the cardiac muscle formed?
Alternating segments of thick and thin protein filaments (myosin and actin)
What is the difference between cardiac and skeletal muscle?
Cardiac muscle cells may be branched instead of linear or longitudinal
What are the four types of tissues?
Epithelial, connective, muscle, and nervous
The electrical signals created by the SA node in the heart follow what electrical pathway?
The natural electrical pathway through the heart/chamber walls
When the electrical signal in the heart passes through a chamber wall and then out of the wall, what happens?
The chamber contracts then relaxes
What is a normal sinus rhythm?
Heart beats at a normal rate (60-100 bpm). All complexes normal
What is a bradycardia rhythm?
The heart beats at less than 60 beats per minute
What is a sinus arrhythmia?
Abnormal rhythm or heart rate, where impulses originate at the SA node at a varying rate
What is the bundle of His in the heart?
Long segment of cardiac muscle cells specialised for electrical conduction from the AV node to the apex of the heart, leading to Purkinje fibres
Are contracted chambers systolic or diastolic?
Systolic (there is atrial systole but systole refers to ventricular contraction)
What is the function of the left hemisphere of the brain?
Comprehension, logic, speech, arithmetic and writing
What is the function of the right hemisphere of the brain?
Creativity, imagination, arts, visual spatial skills and emotions
What is the function of the medulla oblongata in the brainstem?
It controls respiratory, vasomotor and cardiac function (blood pressure and heartbeat)
How many cranial nerves are there and do they come singly or in pairs?
12 and in pairs for each side of the body
What is the functions of the vagus nerve? (also known as tenth cranial nerve)
Digestion, heart rate (to decrease only), breathing and cardiovascular activity
Where do the cranial nerves arise from?
The olfactory (smell) and optic (sight) nerves come from the cerebrum, whereas the other 10 nerves come from the brain stem
How does the medulla oblongata know when to increase or decrease the heart rate?
Baroreceptors detect changes in blood pressure and chemoreceptors detect changes in oxygen and pH change (eg CO2). These send signals to indicate a change is needed.
What is the function of the limbic system?
Behaviour, memory and emotions
Parkinson’s disease is caused by a loss of neurons in the substantia nigra, what does these neurons do?
This area controls movement and also produces dopamine
What is the structure of a single unit of a protein chain and what is it called?
Amino acid and it is an amine group, carboxyl acid group, R group and alpha carbon
What are lymphocytes and which protein family do they secrete in order to fight infections?
A type of white blood cell and they make antibodies (this is the protein type)
What are white blood cells also called?
Leukocytes
What are cytokines?
They are proteins that help control inflammation in the body (boosts immune system)
What are the three sections of the brain stem in descending order?
The midbrain, pons, and medulla oblongata
What does the brainstem do?
It connects the brain and spinal cord
What is the function of the midbrain in the brainstem?
It is a relay system that transmits information for vision, motor movement and hearing between different portions of the brain
What is the function of the pons in the brainstem?
Connects to the cerebellum, regulates breathing and involved in sleep cycle control (unconscious activities)
What is epilepsy and how does this arise?
A CNS disorder that involves recurrent seizures from excessive and abnormal neuronal activity in the cortex of the brain
How can epilepsy be diagnosed?
Using an EEG or neuroimaging via CT or MRI
What does the portal vein do?
It carries venous blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver
What do the hepatic veins do?
They carry venous blood from the liver into the inferior vena cava to go to the heart
What are the different layers in the structure of an artery?
Tunica externa, tunica media and tunica intima
Which layer of the artery is the thickest and is mostly smooth muscle?
The tunica media
How do the kidneys regulate blood pressure?
Control sodium and water balance
What are the two types of bone material structure?
Compact/cortical bone and cancellous/trabecular bone (spongy)
What nerves innervate the heart?
The vagus nerve and accelerans nerve
Auditory reception, speech, language, memory retrieval and emotion are associated with which lobe of the brain?
Temporal lobes
How many genes do humans have roughly?
25,000
When does blood flow through the coronary arteries?
During diastole
Interleukin 6 is what type of molecule?
Cytokine
How many pairs of spinal nerves are there along the spinal cord?
31
Is the vagus nerve a sensory or motor nerve?
Both
What is chemotaxis?
The movement of a cell or organism passing along a concentration gradient either toward or away from the chemical stimulus
What is the High Frequency (HF) Heart Rate Variability Parameter an indirect measure of?
Assessing the status of the parasympathetic and sympathetic autonomic nervous system
What is the primary function of the baroreflex response/baroreceptor reflex?
To maintain adequate blood supply to the brain when moving between a supine and standing position
Is epinephrine a hormone or a neurotransmitter and what is it also known as?
Both and adrenaline
What artery carries blood across the knee?
Popliteal
Do arteries have valves and why?
No because the force of the blood from your heart ensure the blood only goes in one direction
Do arteries or veins have thinner walls?
Veins
Where do the coronary arteries supply blood to?
The heart
Where do the carotid arteries supply blood to?
Brain, face and neck
Where do the vertebral arteries supply blood to?
Brain and spine
Where do the iliac arteries supply blood to?
Pelvis
Where do the femoral arteries supply blood to?
Legs
Where do the subclavian arteries supply blood to?
Head, neck and arms
Where do the celiac and mesenteric arteries supply blood to?
Digestive system
What does adenine combine with in DNA and RNA?
Thymine (DNA) and uracil (RNA)
What is the complement system in the blood and what is it primarily concerned with?
Large number of plasma proteins and is it for immune defence
What is the food type with the highest energy value?
Lipids (fats)
What is the periosteum with regards to bones?
It is a tough, thin membrane that covers the outer surface of all bones
What are the types of bones? (not the types of bone tissue)
Long, short, flat and irregular
What is the medullary cavity?
The hollow part of bone that contains bone marrow to manufacture red blood cells
What is the alternative name for a platelet?
Thrombocyte
The first stage of wound healing (hemostasis) has what three steps?
Vasoconstriction, temporary blockage by a platelet plug and blood coagulation
A stroke can cause a seizure, can a seizure does cause a stroke?
No
What is the largest risk factor for a stroke or seizure?
Hypertension (high blood pressure)
What is the obligatory volume of urine per day?
350 ml
What are anti-diuretic hormones and where are they made and secreted?
Regulates the amount of water in your body. Made in the hypothalamus but secreted by the pituitary gland
What is sinus tachycardia?
Regular cardiac rhythm with a fast heart rate (over 100 beats per minute)
What is atrial fibrillation?
A type of arrhythmia defined by a irregularly irregular rhythm and disorganised atrial electrical activity and contraction. No P waves, irregular baseline
What is pharmacology?
The science of drugs and their effect on living systems
Why is the study of pharmacology important?
Development of new drugs and formulation of clinical guidance for safe and effective treatment of disease
What is the therapeutic index in terms of pharmacology?
It is margin of safety of the ratio of therapeutic effect and toxic side effect
Does the therapeutic index take into account drug selection, dosage selection or both?
Both
How is DNA, histones, nucleosome, chromatin, and chromosomes linked together?
DNA wraps around histones to make nucleosomes which coils into a chromatin fibre, which forms together to make a chromosome
What constitutes the organisms genome?
The complete set of chromosomes (ie complete genetic info for an organism)
Does smooth muscle consist of striations?
No
What is the role of principle or excitatory neurons?
They are responsible for communicating with other neurons
What is genetics?
The study of hereditary and variation of inherited characteristics
What is heredity?
The tendency of offspring to resemble their parents through the passing of genes
What is variation in genetics?
The tendency of offspring to vary from their parents
What does cytosine always pair with?
Guanine
What are the repeating units that make up DNA?
Nucleotides
What are the components of nucleotides?
Nitrogen-containing base, a phosphate group and a sugar molecule (deoxyribose for DNA)
What are chromosomes made of?
Tightly packaged structure of DNA with associated proteins (eg histones)
How many chromosomes do humans have?
46 (23 pairs)
What is a gene?
A segment of DNA that contains the biological instruction to make a particular polypeptide (protein)
What is an allele?
Alternate forms of a gene found at the same place on a chromosome
How many alleles do you inherited from each parent?
One allele for each gene
What is a codon?
A sequence of three nucleotides, which encode for a particular amino acid
How many amino acid types are there?
20
What is a variant in genetics?
Any differences between the sequence of two individual or a reference genome
Are variants in genetics harmless?
They could be harmless (benign) or disease causing (pathogenic)
What is a genotype?
The hereditary information or genetic code
What is a phenotype?
The physical characteristics. The observable expression of the genotype and also depends on a persons environment
If the alleles are the same, is the organism homozygous or heterozygous for that trait?
Homozygous
If the dominant allele is present, will the recessive allele ever show as the phenotype?
No, the dominant allele always wins
When will a recessive allele be expressed in the organisms phenotype?
If the genotype is homozygous recessive
What is the difference between genomics and genetics?
Genomics is the study of an organism’s complete set of genetic information, whilst genetics is the study of hereditary and the study of the function and composition of single genes
How many autosome chromosomes do we have and what is left?
22 pairs of autosomes and the 23rd pair is the sex chromosomes
What is meiosis?
A type of cell division where a single cell divides twice to produce four (non-identical) daughter cells - gametes (sperm or egg cells)
After meiosis, each gamete is haploid, what does this mean?
They only contain a single set of 23 unpaired chromosomes
When two haploid gametes come together in reproduction, they form an organisms diploid genome, what is this called?
A zygote
What is mitosis?
The process by which a zygote produces two identical cells through cell division
After mitosis, the two cells are called daughter cells, what do they do?
They divide to produce two new cells and so on
When do cells in our body undergo mitosis?
In our growth and development and to repair tissue or replace dead cells
What is germline or constitutional variation?
Variants that occur during meiosis can be inherited (as the variant is present in every cell, including gametes)
Can variants that occur during mitosis be inherited?
No
What is somatic variation?
Variants that occur during mitosis
The extent of the cells affected by somatic variation depends on what?
The stage of development at which the variant occurred
Can DNA errors be repaired by DNA enzymes?
Some can but some errors persist
What are the different types of DNA mutation?
Substitution, insertion, deletion or frameshift
Where in the body can somatic variants occur?
Any cell except those of the germline
Are females XX or XY?
XX
What are the two types of chromosomal abnormalities?
Numerical and structural
What are numerical chromosomal abnormalities?
Whole chromosomes either missing from or extra to the normal pair
What are structural chromosomal abnormalities?
Part of an individual chromosome is missing, extra, switched to another chromosome or turned upside down
What is a karyotype?
An organised profile of a person’s chromosomes, eg a normal male chromosome pattern is 46, XY
What is a carrier in genomics?
An individual who has a variant associated with a genetic condition and can pass it on to their children but does not have the condition themselves
What is a de novo variant?
A variant that arises in a person’s DNA for the first time and not inherited by a parent
What causes a monogenic condition?
A pathogenic variation in a single gene. They can be dominant or recessive, and autosomal or sex-linked
What causes a polygenic condition?
Pathogenic variants in multiple genes
What causes a multifactorial condition?
A combination of pathogenic variants and environmental factors
What are the common modes of inheritance of genetic conditions?
Autosomal dominant, autosomal recessive, X-linked recessive, X-linked dominant, de novo
What is autosomal dominant inheritance?
A condition caused by a mutation in a gene that is dominant in one of the autosomes (not sex chromosomes)
Do males and females have an equal chance of passing on a mutation caused by autosomal dominant inheritance and why?
Yes because it is not passed on via the sex chromosomes
What is an example of a condition passed on by autosomal dominant inheritance?
Huntington’s disease
What is required for someone to receive a condition that is passed by autosomal recessive inheritance?
Both parents must be carriers of the mutation for it to be possible (25% chance)
What is autosomal recessive inheritance?
A condition caused by a mutation in a gene that is dominant in one of the autosomes
What is an example of a condition passed on by autosomal excessive inheritance?
Cystic fibrosis
On family diagrams, are males represented by squares or circles?
Squares
Does the X or Y chromosome have more genes?
X
What is X-linked recessive inheritance?
Variants in recessive genes on the X chromosome
Why are males more likely to be affected by X-linked recessive disorders than females?
Males have only one X chromosome so one altered copy of the gene is sufficient to cause the condition, whereas females require a variant in both copies of the gene to cause the disorder
Can fathers pass X-linked inheritance traits to their sons and why?
No because the father provides the Y chromosome for their sons
What is X-linked dominant inheritance?
Variants in dominant genes on the X chromosome
Are both males and females affected by X-linked dominant conditions if there is a single copy of the mutation for either?
Yes because it is dominant (males are more likely to be severely affected though)
Can de novo mutations be inherited?
Yes
What is genome sequencing?
Determining the exact order of the bases in a strand of DNA (can use this to determine other strand as matching base pairs)
What is genome sequencing by synthesis?
DNA polymerase (enzyme) used to generate a new strand of DNA from a strand of interest and enzymes use chemically tagged nucleotides with a fluorescent label
Who analyses and assesses a genomic test in the NHS before it is passed on to the clinical team?
MDT, including bioinformaticians, clinical scientists and clinical geneticists
What are the two categories of genetic testing methodologies used by the National Test Directory?
Cytogenetic - detects abnormalities in chromosome structure
Molecular - detect abnormalities in DNA sequence
Who is in the Clinical Genetics team?
Consultant Geneticists, Genetic Counsellors, Family History Collection Coordinators, research nurses and coordinators and administrative support
What is genetic counselling?
A communication process which deals with human problems associated with the occurrence or risk of occurrence of a genetic disorder in a family
What are the possible benefits of genetic counselling?
Increased knowledge, perceived personal control, positive health behaviours, improved risk perception accuracy, decrease in anxiety, and decisional conflict
What is the National Genomic Test Directory?
A public document that specifies which genomic tests are commissioned by the NHS in England
How many base pairs (bp) does the human genome contain?
3.2 billion
A typical healthy human will have how many differences to the reference genome?
3 million (ie 99.9% the same)
Since variation across genomes is normal, what methods can help identify if a change to the genome is disease-causing?
Genome mapping, gene function studies, healthy and diseased population genomic data sets, testing technologies and bioinformatics
What are some types of genetic testing technologies?
Micro array, karyotypes, MLPA, next generation sequencing
What are the 4 ethical considerations for genetic testing?
Autonomy (informed consent)
Justice (fairness and equality)
Beneficence (duty of care)
Non-maleficence (no harm to patient)
In the informed consent process for genetic testing, what details should be included in the discussion?
Briefly explain normal genes and chromosomes, family history, need for samples, limitations of testing, possible outcomes and consent and storing of DNA
Should genetic testing focus on what is ethically right or wrong, or focus on what is clinically right or wrong?
Ethically
What is the difference between secondary and incidental findings in genomic testing?
Secondary = Variants in disease-causing genes that are unrelated to the phenotype but actively sought
Incidental = unrelated to the phenotype and identified by chance
Which of the following are true? Genomic test results can be diagnostic, predictive, uncertain, incidental or secondary
All of them
What is pharmacodynamics?
The effect the drug has on the body (remember that this is the effect of the Drug = Dynamics)
What are the two classes of interaction in pharmacology?
Pharmacodynamics and pharmacokinetics
What is pharmacokinetics?
The effect that the body has on the drug over time
What are the components of pharmacokinetics and its acronym?
Absorption, distribution, metabolism and excretion. ADME
What is the equation for the therapeutic index?
The concentration required to have a toxic effect in 50% of the population studied divided by the concentration required to have a therapeutic response
If you increase the dose of a drug with a small (narrow) therapeutic index, the probability of what increases?
The probability of toxicity or ineffectiveness of the drug
What graph type is used to work out the therapeutic index?
Dose-response curve with % responding on the y-axis and amount of the drug on the x-axis
What are receptors and ligands in pharmacology?
Drugs are considered to bind to receptors (protein molecules) and any chemicals that bind to a site on a receptor are ligands
What is affinity in pharmacology and is it the same as potency?
The strength of the binding of a ligand (drug) and its receptor. Yes
What is efficacy in pharmacodynamics?
The maximal effect a drug can produce
What is the difference between specificity and selectivity in pharmacodynamics?
Specificity is when a drug has a particular effect and not another. Selectivity is when a drug acts on a particular receptor and not another
Why are there no truly specific drugs?
They all have side effects
Drug receptors normally respond to endogenous compounds in the body, what does this mean?
Compound originates from within the body, like hormones or transmitter substances
If a drug or transmitter substance produces a response in a cell, it is called what?
Agonist
If a drug or transmitter substance (neurotransmitter) reduces of blocks a response in a cell, it is called what?
Antagonist
What properties does a drug require for it to be absorbed by any route of administration? (pharmacokinetics)
Able to be transported across a membrane (uncharged, low molecular weight and high lipid solubility), bioavailability, stability of drug depends on route and formulation
What is bioavailability?
The proportion of the drug that reaches its intended site and give its effect eg 100% bioavailability if straight into plasma for IV administration
What is the first pass effect in pharmacology and how does this effect bioavailability?
Metabolism, which reduces bioavailability as a lower fraction of the drug will get to its intended site
What is the volume of distribution (Vd) in pharmacokinetics?
The apparent volume into which the drug is distributed
What types of drugs will have high volume of distribution (Vd) and which will have low?
High Vd = lipid soluble drugs
Low volume = drugs that are highly ionised or have large molecular weight
What is the steady state of a drug (Css)?
It occurs when the amount of a drug being absorbed is the same amount that’s being cleared from the body when the drug is given continuously or repeatedly.
What are excretion methods of a drug?
Urine, faeces, milk, sweat and expired air
How are most drugs excreted?
Renally (through the kidneys)
What is first-order kinetics of elimination?
A constant proportion (eg. a percentage) of a drug is eliminated per unit time (exponential decay)
What is zero-order kinetics of elimination?
A constant amount (eg. milligrams) of drug is eliminated per unit time (linear). Independent of how much initially given
Do most drugs follow first or zero order kinetics of elimination?
First order
Do first or zero order kinetics of elimination have half lives?
Both
Are drugs more or less toxic with zero order kinetics of elimination?
More as its not being cleared as quickly
What features are used to determine dosing schedules in pharmacology?
Half life, clearance, steady state and bioavailability
Do drugs have to be more or less lipid soluble to be excreted by the kidneys?
Less
How do drugs become less lipid soluble?
Phase I and Phase II metabolism
What factors may affect drug metabolism?
Enzyme induction or inhibition, pharmacogenetic variation and age
What are type A adverse drug reactions?
An exaggeration of a drug’s
normal pharmacological actions when given at the usual therapeutic dose and are normally dose-dependent (predictable)
What are type B adverse drug reactions?
Immunological reactions (not predictable and more rare)
How many genes do humans have approximately?
25,000
What type of protein is responsible for chemically modifying DNA as cells mature?
Enzymes
What is gene expression?
The process by which DNA instructions convert into proteins with two key stages: transcription and translation
What is the first process of gene expression?
Transcription = enzymes (like RNA polymerase) use one of the strands (antisense strand) of DNA within a gene as a template to produce mRNA, which leaves the nucleus and goes into the cytoplasm to a ribosome for translation
What happens in translation?
Each codon of mRNA passes through the ribosome and interacts with the anticodon of a specific transfer RNA (tRNA) molecule, which carries a specific amino acid, and this continues to form a chain of amino acids
Does the sympathetic nervous system have long or short preganglionic and postganglionic nerves?
Short preganglionic nerves and long postganglionic nerves
What neurotransmitter does the sympathetic nervous system use?
Noradrenaline (norepinephrine)
What neurotransmitter does the parasympathetic nervous system use?
Acetylcholine
Does the parasympathetic nervous system have long or short preganglionic and postganglionic nerves?
Long preganglionic nerves and short postganglionic nerves
Why does the parasympathetic nervous system have longer pre-ganglionic nerves than the sympathetic nervous system?
It is more localised, whereas activation of the sympathetic nervous system is more widespread
What are the major types of muscle?
Cardiac, skeletal (also called striated muscle) and smooth
What are the main differences between skeletal and cardiac muscle?
Cardiac muscle cells are joined end to end and the signal flows through them and 40% of heart muscle is mitochondria
What is a motor unit?
A motor neuron and all of the skeletal muscle fibres innervated by the neuron’s axon terminals. It is the basic functional unit of the skeletal muscle
What are neuromuscular junctions?
Connection between the terminal end of a motor nerve and a muscle, where the transmission of action potentials occur.
What are muscle fibres called?
Myocytes
What do myocytes contain?
Thousands of myofibrils
What is each myofibril composed of?
Numerous sarcomeres, which is the contractile region of striated muscle
What are sarcomeres composed of?
Myofilaments of myosin and actin, which interact using the sliding filament model
What is the sarcolemma?
Cell membrane of a myocyte
What are sarcomeres?
The smallest functional unit of striated muscle tissue and it is the repeating unit between two Z lines
What is ATP composed of?
Adenine molecule, ribose molecule and 3 phosphate groups
What are the steps of contraction and relaxation of skeletal muscle?
ATP hydrolysis, formation of cross-bridges (myosin head attached to myosin-binding site on actin), power stroke (sliding filaments) and detachment of myosin from actin
What ion is given in skeletal muscle from action potentials?
Calcium ions
Where are smooth muscles in the body?
Blood vessel walls, stomach, intestines, bladder, and uterus
Since there are no sarcomeres in smooth muscle, how are the fibres arranged?
They are grouped in branching bundles (nodes that the filaments run up against)
What is cartilage?
Strong, flexible connective tissue that protects your joints and bones.
What are tendons for?
Bone-muscle attachments
What are ligaments for?
Bone-bone tissue
Is bone a type of connective tissue?
Yes
What is bone composed of?
A rigid matrix of calcium salts deposited around protein fibres (mostly collagen)
In bone, what do minerals provide?
Rigidity
In bone, what do proteins (mostly collagen) provide?
Elasticity and strength
What are some features of long bones?
Hollow to save weight, reservoir for body’s mineral content, engine of blood cell manufacture
What are the interstices of cancellous bone filled with?
Marrow
Where is cortical bone?
Around all bones beneath the periosteum and primarily along the shafts of long bones
Where is cancellous bone?
In vertebra, flat bones and the ends of long bones
What percentage of skeletal mass is cortical bones?
80%
Does cortical or cancellous bone withstand greater stress and strain?
Greater stress = cortical (force per unit area)
Greater strain = cancellous (change in shape from force exerted)
Is cortical or cancellous bone better at withstanding bending and twisting?
Cortical
Is cortical or cancellous bone better at withstanding compression?
Cancellous
Does cortical or cancellous bone have higher stiffness?
Cortical
What are the 3 types of bone cells?
Osteoblasts, osteoclasts and osteocytes
What do osteoclasts do?
Degrade bones (re-modellers)
What do osteoblasts do?
Create new bone
What are osteocytes?
Mature bone cells (used to be osteoblasts) and they are responsible for the maintenance of the bony matrix
What are the three types of joints?
Cartilaginous, fibrous and synovial
What are synovial joints?
Freely movable joints that have synovial fluid in the joint cavity and cartilage around the bones
What are fibrous joints?
Bones connected by fibrous tissue
What are cartilaginous joints?
Bones joined by cartilage
What is the order of joint types from most to least freely movable?
Synovial, cartilaginous, fibrous
Where are fibrous joints?
In the skull
Where are cartilaginous joints?
Intervertebral discs
What are different types of cartilage?
Hyaline cartilage (surrounds bones in joints), fibrocartilage (intervertebral discs) and elastic cartilage (ear)
What are fracture types of bones?
Complete, incomplete, impacted, transverse, comminuted (shattered section), open (pierced the skin), closed, spiral and oblique
What are the stages of bone fracture repair?
Hematoma formation, callus formation (cartilage and fibres), callus ossification, bone remodelling
What are the Basic Multicellular Units (BMUs) of bone remodelling?
The cells responsible for bone remodelling, including osteoclasts and osteoblasts
How long does is take for bone to be completely remodelled?
Approximately 3 years
What are the major factors for bone remodelling?
Hormones (oestrogen and testosterone) and cytokines (growth factors, interleukins, transforming growth factors)
What is the haematocrit and values for males and females?
The percentage of volume of red cells in your blood. Male: 44%, female: 42%
What are the sections of blood after centrifugation and the rough percentages of each?
Plasma (55%), buffy coat (<1%), red blood cells (45%)
What cells are in the buffy coat of blood?
Platelets (thrombocytes) and white blood cells (leukocytes)
Is the distribution of the velocity of blood in vessels parabolic or linear what does this mean?
Parabolic so blood is faster in the middle and slower near the outer edges
What is the size of red blood cells?
7 microns (micrometres)
What is the diameter of capillaries?
5 microns
Is blood viscosity constant in the body?
No
Are white blood cells bigger or smaller than red blood cells?
Bigger (12 microns vs 7 microns)
What are clotting/coagulation factors?
They are components found in plasma that are part of the blood clotting process
What clotting factor is part of the blood clotting/coagulation process?
Fibrinogen converted to fibrin
An atomic mass unit is also called what?
A Dalton
What is the mnemonic for types of white blood cells (leukocytes or immunocytes)? The order is representative of the proportion of them
New (neutrophils)
Lawn (lymphocytes)
Mowers (monocytes and macrophages come from monocytes)
Eat (eosinophils)
Best (basophils)
Which parts of the blood do not have a nucleus?
Red blood cells and platelets
What is the name for red blood cells?
Erythrocytes
What are phagocytes?
A type of immune cell that can surround and kill microorganisms. It includes monocytes, macrophages (including microglial cells), and neutrophils
What do erythrocytes (red blood cells) contain for them to carry oxygen?
Haemoglobin (which contains 4 iron atoms that are binding sites for oxygen)
What is the main function of the kidneys and why?
Produce urine to maintain homeostasis
What are the contributions from the renal system to homeostasis?
Maintenance of water balance, blood pH and electrolyte balance
What connects the kidneys and the bladder?
Ureters
What comes in and out of the kidneys and how?
In: unfiltered arterial blood via the renal artery
Out: filtered venous blood via the renal vein and urine via the ureter
What is the basic functional unit of the kidney?
Nephron
What is the basic premise of how nephrons in the kidney work?
They create a gradient of osmotic pressure to drive water out of the tubule
What is the two step process of nephrons?
The glomerulus filters your blood and the tubule returns needed substances to your blood and removes waste
What is Starling’s law?
The stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles
What is stroke volume?
The volume of blood pumped out of the left ventricle of the heart during each systolic cardiac contraction
What is the diameter range for arteries and veins?
0.04 - 10 mm
What do precapillary sphincters do?
Adjust blood flow into capillaries
What force drives fluid out of capillaries and into the tissues?
Hydrostatic pressure
What is arteriosclerosis and what is a type of it?
Hardening of the arteries, and atherosclerosis - plaque build up (some people use these interchangeably)
Heart valves are made of flaps, what are these called?
Leaflets
What is an aneurysm?
Outward bulging (bubble or balloon) caused by a localised weak spot on a blood vessel with a high risk of rupture
What is a stroke?
Loss of blood supply to the brain
What are the main causes of a stroke?
Haemorrhage (bleeding from a damaged blood vessel), thrombosis (obstruction of a blood vessel by a blood clot forming locally)
embolism (obstruction due to an embolus (clot or plaque) from elsewhere in the body)
What is the structure of the lungs?
There are 2 bronchi (one for each lung), which branch into bronchioles to reach alveoli (air sacs), which are surrounded by a network of capillaries
What muscles cause the breathing movements?
The diaphragm and intercostal muscles
What does the diaphragm do during inhalation and exhalation?
In inhalation, it contracts so that its centre moves downwards and the edges move upwards to expand the thoracic cavity and draw air into the lungs. In exhalation, the diaphragm relaxes to decrease the size of the thoracic cavity and expel air
What are glial cells?
Any of the cells that hold nerve cells in place and help them work the way they should (mechanical and metabolic support)
How much of the brain volume is glial cells?
50%
Is there more glial cells or neurons?
Glial cells (10-50 times more)
Extensions of the neuron cell body include dendrites and axons, what are these known as?
Processes
What are interneurons?
Neurons in the CNS that connect the sensory and motor neurons
What are the three types of neurons?
Sensory, motor and interneurons
What are excitatory and inhibitory neurotransmitters?
Excitatory neurotransmitters promote the generation of action potentials in the next neuron, whereas inhibitory neurons inhibit it
What are unipolar neurons?
They have only one process extending from the cell body (soma). Pseudounipolar neurons have one process that splits into two branches
What are bipolar neurons?
They have an axon and a dendrite extending from the cell body
What are multipolar neurons?
One axon and many dendrites extending from the cell body
What is the most common neuron structure in vertebrates?
Multipolar neurons
What are some of the functions of glial cells?
Surround and support neurons. Separate and insulate groups of neurons. Produce myelin. Uptake and removal of chemical transmitters.
What are the 4 types of glial cells in the CNS?
Astrocytes, oligodendrocytes, microglia and ependymal cells
What are the 2 types of glial cells in the PNS?
Schwann cells and satellite cells
Astrocytes are involved in what types of diseases?
Neurodegenerative diseases, like Alzheimer’s disease
What characterises Alzheimer’s disease?
Memory loss and cognitive dysfunction
What do oligodendrocytes do? (type of glial cell)
Wrap axons with myelin sheath in the CNS
What disease is caused by injury to oligodendrocytes and demyelination in the CNS?
Multiple sclerosis
What do astrocytes do? (type of glial cell)
Fills spaces between neurons and influence neural synapses
What do microglia do?
Immune cells of the CNS and monitor brain tissue for signs of disease/damage and respond to pathogens by destroying them (phagocytes)
What do satellite glial cells do?
They cover the surface of neuron cells bodies in ganglia in the PNS
What are the 4 lobes of the brain?
Frontal, parietal, occipital and temporal
What is grey matter?
The surface of the cerebral cortex and is associated with processing and cognition. It contains mostly neuron cell bodies and less myelinated axons
What is white matter?
Bulk of the deeper parts of the brain and consists of glial cells and myelinated axons
What is the pre-frontal cortex responsible for? (anterior portion of frontal lobe)
High cognitive function, language and intellect
What is the parietal lobe responsible for?
Receives and processes sensory input, like touch, heat and pain
What is the temporal lobe responsible for?
Speech, language and processing sounds. (remember temporal = talking) Memory and emotion
What is the occipital lobe responsible for?
Object recognition and processing visual information
What lobe of the brain being damaged would create personality and behavioural changes?
Frontal lobe
What mnemonic can be used to remember the parts of the limbic system?
Hippo HAT
Hippocampus
Hypothalamus
Amygdala
Thalamus
What is the hippocampus responsible for?
Memory and learning
What is the amygdala responsible for?
Fear and emotions
What is the hypothalamus responsible for?
Links to endocrine system - produces hormones to maintain homeostasis (temp, metabolism etc)
What is the thalamus responsible for?
Sensory relay station to cerebral cortex
How many pairs of nerves branch off from the spinal cord?
31
Each spinal cord segment that leads to a spinal nerve is formed by a combination of what on each side (left and right)?
A dorsal root carrying afferent sensory axons and a ventral root carrying efferent motor neurons. They are separate near the spinal cord then unit to form mixed nerves
In the spinal cord, where is white and grey matter?
White matter at the surface and grey matter inside
What areas do the internal and external carotid arteries supply blood to?
External: supplies all structures of the head except the brain (skin, muscles, bones etc) and internal: brain and eyes
Mesial Temporal Sclerosis (MTS) is the scarring of the temporal lobe, which can cause what?
Temporal lobe epilepsy
Schizophrenia is a CNS disorder, what characterises this disorder?
Significant impairments in the way reality is perceived and changes in behaviour
What are potential causes for schizophrenia?
Differences in brain chemistry and structure, or substance abuse
How is schizophrenia characterised on an MRI?
Enlarged lateral ventricles
Parkinson’s disease is a CNS disorder, what is this?
Progressive depletion of the neurotransmitter dopamine and neuronal loss. It is characterised by slow movements and a tremor
What images can Parkinson’s disease be diagnosed?
MRI scans but normally only in later stages
What rude mnemonic can be used to remember the cranial nerves in order?
Oh Oh Oh To Touch And Feel A Girls Vagina, Ah Heaven
What does the ‘oh oh oh’ part of the cranial nerve rude mnemonic stand for?
Olfactory (nose), optic (eye), oculomotor (eye muscles)
What does the ‘to touch and feel’ part of the cranial nerve rude mnemonic stand for?
Trochlear (eye movement), trigeminal (facial sensations), abducent (move eyes), facial (face muscles)
What does the ‘a girls vagina’ part of the cranial nerve rude mnemonic stand for?
Auditory/vestibular (hearing and balance), glossopharyngeal (taste and swallow), vagus (digestion and heart rate)
What does the ‘ah heaven’ part of the cranial nerve rude mnemonic stand for?
Accessory (shoulder and neck muscle movement), hypoglossal (tongue muscles)
What mnemonic can be used to remember if a cranial nerve is sensory, motor or both?
Some Say Marry Money But My Brother Says Big Brains Matter Most
What is an electrocardiogram (ECG)?
Surface measurement of the electrical potential generated by electrical activity in cardiac tissue by placing electrodes on the body’s surface
An ECG signal may look different if a portion of the heart muscle is damaged or dead, why?
This portion of muscle will block the electrical transmission through that area
The direction and magnitude of deflection of an ECG trace depends on what?
How the electrical forces are aligned to a set of specific reference axes, known as ECG leads
What is an ECG reading when the heart is in its resting state where the surface of the cell is positive relative to its inside?
No potential difference (as homogeneously charged) so flat line
Is an ECG extracellular or intracellular? What does this mean when it shows a positive deflection?
Extracellular. A positive deflection is the action potential moving towards the positive electrode because the outside of the cell is negative at one end and positive at the end closer to the electrode
During repolarisation, the current could be directed away from the positive electrode (outside of cell is negative closer to positive electrode). What will show on the ECG?
A downward deflection
What does the P wave on an ECG signal represent?
Depolarisation of the atria
What does the QRS complex on an ECG signal represent?
Depolarisation of the ventricles
Where is atrial repolarisation on an ECG signal?
Hidden behind the QRS complex typically
What does the T wave on an ECG signal represent?
Repolarisation of the ventricles
Is repolarisation in the heart usually faster or slower than depolarisation?
Slower
What is the time between heart beats measured on an ECG?
Peak of QRS complex to the next peak (R-R interval)
What does the PR interval on an ECG signal represent?
Time taken for excitation to spread from the SA node through atrial muscle and AV node down to the bundle of His and into ventricular muscle
Why does the AV node delay the SA nodes electrical signal?
Ensures the atria are empty of blood before the contraction stops
What does the length of time of the QRS on an ECG signal represent?
The time it took for the excitation to spread through the ventricles
What is the typical time for the QRS complex on an ECG?
120 ms
What does the Q wave on an ECG signal represent?
It is a small negative deflection that is the depolarisation of the septum, which occurs left to right (rather than the main conduction direction of right to left)
What does the S wave on an ECG signal represent?
It is a small negative deflection that is the depolarisation in the Purkinje fibres, which are in the opposite direction to the R wave conduction
What could sinus bradycardia be a consequence of?
Increased vagal or parasympathetic tone
What is a nonsinus atrial rhythm?
Origin of atrial contraction located away from SA node, so atrial depolarisation occurs in opposite direction so P wave on ECG deflects downwards
What is a wandering pacemaker as an ECG diagnosis and what will it look like on an ECG trace?
Impulses originate from varying points in the atria so P waves will vary in polarity and PQ time will vary
What is an atrial flutter and what does it look like on an ECG?
Type of arrhythmia, where impulses travel in a circular course in the atria and atria beat too quickly, so ECG has no break between T wave and P wave. Flutter waves.
What is a junctional rhythm?
Type of arrhythmia, where heartbeat originates from the AV node
What is a premature ventricular contraction?
The heartbeat is initiate by the Purkinje fibres in the right ventricle rather than the SA node so it occurs a before a regular heart beat
What is ventricular tachycardia?
Type of arrhythmia, where impulses originate at ventricular pacemaker
What is ventricular fibrillation?
A type of arrhythmia, where there is chaotic ventricular depolarisation (spasmodic twitching). ECG shows rapid, wide irregular ventricular complexes and blood flow ceases
