End of Module Formatives Flashcards
Give 3 features of skeletal muscle
- Striated cytoplasm
- Myofibrils being in register
- Nuclei which are present against the cell membrane
Give 3 features of cardiac muscle
- Striated
- Compromises of branched fibres
- Central nuclei
What does the myometrium compromise of?
- Smooth muscle
- Lacks striatum
- Central nuclei
Name 4 things which the cell membrane contains
- Cholesterol
- Glycolipids
- Lipoproteins
- Phospholipids
What enzymes catalyses the reversible reaction between 1,3-bisphosphoglycerate and what pathway is it part of?
Phophoglycerate kinase & aerobic glycolysis pathway
Name 4 enzymes which are involved aerobic or anaerobic glycolysis
- Aldolase
- Hexokinase
- Phosphoglucose isomerase
- Triose phosphate isomerase
How many calories are there in a unit of alcohol?
56
Name one factor which will lower the basal metabolic rate
Dieting
Define basal metabolic rate
The amount of energy needed at rest to stay alive
Where does oxidative phosphorylation take place?
Mitochondrial matrix
What does ATP synthase do?
Transports protons into the mitochondrial matrix
What does cytochrome C oxidase complex do?
Transports protons out of the mitochondrial matrix
Where does the energy to phosphorylate ADP come from?
Protons
What are 5 features of steroid hormones?
- Lipid soluble
- No storage pool
- Synthesized from cholesterol
- Transported in plasma, bound to carrier proteins
- Bind to intracellular receptors
What are amino acid hormones synthesised from?
Tyrosine
Where do peptide hormones bind?
To plasma membrane receptors
When does implantation of an embryo occur?
When the blastocyst penetrates the endometrial stroma. This occurs 7-8 days after fertilisation
What do epiblasts later become?
Ectoderm
What do paraxial mesoderm cells form?
Somites
Where is the circulation formed?
Lateral plate mesodermal cells (specifically from the splanchnic layer)
How much water does the body roughly contain?
42 litres
How does glucose cross the cell membrane?
By facilitated diffusion
How does cholesterol enter the cells?
By receptor-mediated endocytosis
How does ethanol and oxygen enter cells?
By passive diffusion
How do potassium ions enter cells?
By active transport
What is anticipation (genetically)?
Seen in diseases characterised by trinulceotide repeat disorders, the condition worsens in successive generations
What is gonadal mosaicism?
A condition where a mutation is present in some gamete but not in others. The mutation may be absent from somatic cells (pure gonadal mosaicism)
What is haploinsufficiency?
Where a diploid organism has only a single functional copy of a gene. This gene doesn’t produce enough gene product, hence resulting in disease
What is penetrated (genetically)?
An index of the proportion of individuals with a gene mutation who show it
What is variable expression?
Where some affected have severe effects while others are only trivially affected
What does PICO stand for?
P - patient/problem/population
I - intervention
C - control/comparison/comparator
O - outcomes
Which arteries is the heart supplied by?
The left and right coronary arteries
When does blood flow to the myocardium occur?
During diastole
What does the left coronary artery divide into?
The left anterior descending (LAD) and circumflex arteries
Why is oxygen saturation low in coronary venous blood?
Due to oxygen extraction by the heart muscle being high
Where does the right coronary artery supply?
The interior surface of the heart
Name two things which the liver is responsible for making
- Coagulation factors
- Fibrinogen
What is plasminogen?
The precursor for plasmin.
What is the function of plasmin?
To lyse clots
What is the coagulation cascade?
A series of proteolytic enzymes that circulate in plasma, in an inactive form and generate thrombin when active
What does thrombin do?
Cleaves fibrinogen to create fibrin
What are platelet dense granules and when are they released?
- Released upon cell activation
- Contain a high concentration of a molecule which acts as a agonist at the platelet P2Y12 receptor
What does the mitral valve do?
Prevents the back flow of blood into the left atrium during ventricular systole
What beat is the left ventricle responsible for?
The apex beat, normal palpated in the left 5th intercostal space and midclavicular line
What does the pulmonary vein do?
Carries oxygenated blood from the lungs to the left side of the heart
What does the aortic valve do?
Maintains the systemic diastolic blood pressure by preventing the back flow of blood into the heart during diastole
What does the inferior vena cava do?
Carries oxygenated blood back to the right atrium
What does a T wave represent?
Ventricular repolarisation
What is the normal duration for a PR interval?
0.12 - 0.2 seconds
Which leads assess the electrical activity within the lateral myocardial territory in a ECG?
I, aVL, V5 & V6
What is significant about the aVR lead?
Yields complexes that are normally inverted compared to anterior and inferior leads
Which segment of an ECG may normally be elevated during acute injury/infarction of a substantial myocardial territory?
The ST segment
What does the P wave represent?
Atrial depolarisation
What does the QRS complex represent?
Ventricular depolarisation
How long should the QRS complex be?
Less than 120 msecs
Which chemoreceptors sense PaCO2 levels?
All of them
What centres are important in the control of a human breathing?
Centres in both the pons and medulla oblongata
What nerve innervates the larynx’s main motor function?
The recurrent laryngeal nerve
Where should you go when considering an emergency chest drain?
The second intercostal space (below the second rib)
What is significant about the right main bronchus?
It’s more vertically disposed
How thick is the membrane for the alveolus and haemoglobin for gas exchange?
1 micron
What does the diaphragm do during inspiration?
Contracts and descends
What is the physiological dead space?
The volume of air in the trachea that doesn’t contribute to gas exchange plus the volume of air in the alveoli that doesn’t contribute to gas exchange
What does hypoxia in the lungs cause?
Vasoconstriction
What does arterial PaCO2 depend on?
A constant, the production of carbon dioxide and alveolar ventilation
What is the oxygen/haemoglobin dissociation curve influenced by?
By changing affinity for sequential oxygen molecule binding
What initially happens in respiratory acidosis?
PaCO2 rises
Define FEV1
The volume of air expelled after one second of forced expiration
What is a method to measure gas exchange into the alveolar capillary?
The carbon monoxide signal breath transfer factor
What happens to the pressure of inspired oxygen at ascent?
It falls
What are some of the features of pulmonary oxygen toxicity (Lorraine Smith effect)?
- Shortness of breath
- Cough
- Chest tightness
- Substernal pain
Name 4 of the structures on the transpyloric plane
- Gallbladder
- Pancreas
- Pylorus of stomach
- Duodenum
Where is McBurney’s point located?
1/3 of the distance from the right anterior superior iliac spine to the umbilicus
In which abdominal section is the gallbladder located?
Right hypochondrium
Which nerve supplies the sympathetic and pain fibres to the foregut?
Greater splanchnic nerve
Which spinal nerves does the lesser splanchnic nerve take origin from?
T10-T11
Which nerve is responsible for the sensation of pain in the shoulder caused by inflammation of the gallbladder?
Phrenic nerve
Involvement of which structure is likely when pain from appendicitis become well-localised to the right iliac fossa?
Parietal peritoneum
Which structure is a remnant of the umbilical vein?
Ligamentum teres
Which structure lies in the midline of the anterior abdominal wall?
Linea alba
Which structure lies the most anteriorly in the anterior abdominal wall?
Aponeurosis of the external oblique
Which spinal nerve supplies the dermatome that includes the umbilicus?
T10
Inferior to which line do all of the aponeuroses of the abdominal wall muscles travel anterior to rectus abdominis?
Arcuate line
Name 3 attachments of the rectus abdominis
- Pubic crest
- Xiphisternum
- Costal cartilages of ribs 5-7
Name 4 structures which have a mesentery
- Appendix
- Sigmoid colon
- Jejunum
- Ileum
Name 4 structures which are found in the porta hepatic
- Hepatic artery
- Common bile duct
- Branches of the vagus nerve
- Lymphatics
Which artery supplies blood to the greater omentum?
Gastroepiploic arteries
Name an artery which receives blood from the coeliac axis
Short gastric arteries
Venous blood from which GI structure can drain directly into the systemic venous system, rather than the portal venous system?
Lower oesophagus
Which artery supplies the fungus of the stomach?
Short gastric artery
Where is the plicae circularis found?
The small intestine
Which ligament runs from the anterior liver to the deep aspect of the anterior abdominal wall?
Falciform ligament
Which structure marks the boundary between the foregut and the midgut?
Major duodenal papilla
Which cranial nerve is responsible for the sense of smell?
Olfactory
Which gland is located immediately superior to the sphenoid sinus?
Pituitary gland
Into which area of the nasal cavity does the nasolacrimal duct drain?
Inferior meatus
The Eustachian tube connects the nasopharynx to which other cavity?
Middle ear
Into which area of the nasal cavity does the maxillary sinus drain?
Middle meatus
Which nerve supplies sensation to the maxillary sinus?
Maxillary branches of trigeminal nerve
What is the name of the structure through which olfactory fibres pass to reach the nasal cavity?
Cribriform plate
Which nerve carriers taste sensation to the anterior 2/3 of the tongue?
Chorda tympani
Name 4 structures which form part of the origin of the pectoralis major
- Aponeurosis of external oblique muscle
- Clavicle
- Sternum
- Costal cartilages of ribs 1-6
What is the insertion of pectorals major?
Bicipital groove of humerus
What is the insertion of pectoralis major?
Coracoid process
Which muscle is innervated by the lateral pectoral nerve?
Pectoralis major
Which nerve supplies the Serratus anterior muscle?
Long thoracic nerve
Which bony process does the clavicle articulate with?
Acromion process
Where does lymph from the upper-outer quadrant of the breast drain from?
Axillary lymph nodes
Give 4 functions of the pectoralis major
- Internal rotation of the humerus
- Adduction of the humerus
- Flexion of the shoulder joint
- Accessory muscle for respiration
Which blood vessel is found immediately deep and lateral to the sternum on the inside of the anterior thoracic wall?
Internal mammary/thoracic artery
What is the innervation of the parietal pleura?
Intercostal nerves
What is the innervation of the visceral pleura?
Vagus nerve
What is the innervation of the central diaphragm (sensory and motor)?
Phrenic nerve
What is the innervation of the pericardium (sensory)?
Phrenic nerve
How many fissures are found in the right lung?
2
What is the origin of the phrenic nerve?
C3-C5 spinal nerves
In the hilum of the left lung, where is the pulmonary artery in relation to the bronchus?
Superior
Which organ is responsible for the diaphragm resting higher up in the thoracic cavity in the right compared to the left?
Liver
What is/are the first branch(es) of the aorta
Coronary arteries
Through which valve must blood travel through to get from the left atrium to the left ventricle?
Mitral
Where does the coronary sinus drain into?
Right atrium
In the foetus, which structure shunts blood from the right atrium into the left atrium?
Foramen ovale
In the adult, which structure represents a remnant of the structure that shunted blood from the pulmonary artery into the aorta?
Ligamentum arteriosum
Where does the azygous vein drain into?
Superior vena cava
What is the name of the striated muscular tissue found inside the auricles of the atria?
Musculi pectinati
What is the name of the groove on the external anterior aspect of the heart that represents the location of the SAN?
Suclus terminalis
Which artery most often gives rise to the posterior interventricular artery?
Right coronary
Which structure carries electrical impulses from the AVN dow the cardiac septum?
Bundle of His
Where does the thoracic duct drain into the venous system?
Where the left internal jugular vein meets the left subclavian artery
Which nerve travels alongside the oesophagus as it enters the abdomen?
Vagus nerve
Which spinal nerves does the sympathetic chain receive fibres from?
Thoracic and lumbar spinal nerves
Which artery gives rise to the inferior thyroid artery?
Thyrocervical trunk
Damage to which structure causes Horner’s syndrome?
Cervical sympathetic chain
Thyroxine requires relatively high volumes of which element for its production?
Iodine
The external jugular vein drains into which vein?
Subclavian vein
Which muscle is found most superficially beneath the skin overlying the anterior neck?
Platysma
Which cartilage of the airway is the only complete ring?
Cricoid cartilage
The left recurrent laryngeal nerve loops underneath which structure before it returns back up the neck?
Arch of the aorta
Which nerve carries sensory fibres from the internal larynx above the vocal chords
Internal laryngeal nerve
Which muscle is supplied by the superior laryngeal nerve?
Cricothyroid
What is the name of the recess between the root of the tongue and epiglottis?
Vallecula
Which is the only muscle supplied by the glossopharyngeal nerve (IX)?
Stylopharyngeus
Which nerve supplies taste sensation to the anterior 2/3 of the tongue?
Facial (VII)
Which nerve supplies secreto-motor function to the submandibular salivary gland?
Facial (VII)
Which nerve passes through the substance of the parotid salivary gland?
Facial (VII)
Where does the submandibular salivary ducts open into the oral cavity?
Both sides of the lingual frenulum
Which nerve carries sympathetic and pain fibres to and from the foregut?
Greater splanchnic nerve
Irritation of the diaphragm, which may be caused by inflammation of the gall bladder, causes referred pain to be felt in which part of the body?
Shoulder
Where would oedema quickly develop if there is a sudden rupture of a major papillary muscle in the left ventricle?
Lungs (pulmonary oedema)
Which of the following is a feature of Horner’s syndrome?
Anhydrosis of the face (lack of sweating)
Where is the origin of the Vagus nerve?
Medulla
Where does blood from the cerebral circulation drain?
Into sinuses that are formed between the dura and between meningeal and periosteal dural layers
Does the cavernous receive blood from the orbit?
Yes
Where is CSF re-absorbed?
The superior sagittal sinus
Where does the straight sinus receive venous blood from?
The inferior sagittal sinus and the great cerebral vein
Where does venous blood from the cerebral circulation exit the cranium?
Via the jugular foramina
How does the venous blood return to the heart from the cerebral circulation?
Via the internal jugular veins
Where do the internal jugular veins collect blood from?
The brain, superficial parts of the face and the neck
Where does the blood supply to the brain come from?
- 20% from the two vertebral arteries
- 80% from the internal carotids (ACA & MCA)
Where does the left anterior cerebral artery carry blood to?
The motor cortex of the right leg
Where do the lenticulo-striate arteries carry blood to and what are the branches of?
- They are branches of the ACA & MCA
- Carries blood to the basal ganglia
An embolism in which arteries will infarct the cerebellum?
SCA, AICA, PICA
Name 2 arteries which are a branch of the basilar artery
SCA & AICA
Name an artery which is a branch of the vertebral artery
PICA
Where does blood from the cerebral circulation drain?
Into sinuses that are formed between the dura and between meningeal and periosteal dural layers
Does the cavernous receive blood from the orbit?
Yes
Where is CSF re-absorbed?
The superior sagittal sinus
Where does the straight sinus receive venous blood from?
The inferior sagittal sinus and the great cerebral vein
Where does venous blood from the cerebral circulation exit the cranium?
Via the jugular foramina
How does the venous blood return to the heart from the cerebral circulation?
Via the internal jugular veins
Where do the internal jugular veins collect blood from?
The brain, superficial parts of the face and the neck
Where does the blood supply to the brain come from?
- 20% from the two vertebral arteries
- 80% from the internal carotids (ACA & MCA)
Where does the left anterior cerebral artery carry blood to?
The motor cortex of the right leg
Where do the lenticulo-striate arteries carry blood to and what are the branches of?
- They are branches of the ACA & MCA
- Carries blood to the basal ganglia
An embolism in which arteries will infarct the cerebellum?
SCA, AICA, PICA
Name 2 arteries which are a branch of the basilar artery
SCA & AICA
Name an artery which is a branch of the vertebral artery
PICA
What is the middle cerebral artery a direct continuation of?
The internal carotid artery in the Circle of Willis
Where is Wernicke’s area found?
Temporal lobe
Where is Broca’s area found?
Frontal lobe
What may happen if you have a stroke in the temporal lobe?
Memory loss
What may happen if you have a stroke in the occipital lobe?
Contralateral homonymous hemianopia
What are the typical characteristics of a stroke affecting the internal capsule?
- Haemorrhagic
- Of the lenticulostriate artery
What is the effect of a stroke affecting one side of the motor or sensory cortex?
A contralateral neurological deficit
Where does the primary motor cortex occupy?
The pre-central gyrus
Where is the primary motor cortex supplied by?
The ACA and MCA
What is Brodmann’s area 4?
Primary motor cortex
What is Brodmann’s area 44?
Broca’s area
Are the muscles of the lower limbs represented medially or laterally?
Medially
Are the muscles of the face represented medially or laterally?
Laterally
Where do the corticospinal (pyramidal) tracts originate?
The primary motor cortex
Where do the corticospinal tracts pass to enter the cerebral peduncle (internal capsule)?
Between the basal ganglia and thalamus
Where does the lateral corticospinal tract decussate?
At the level of the medullary pyramids
What is the role of the basal ganglia in Parkinson’s?
An abnormal rhythmical output
Do lower motor neurones innervate directly?
Yes
Where are axons of the upper motor neurons mainly located?
In the lateral white matter of the spinal cord
Where are the cell bodies of the lower motor neurones located?
In the ventral horn of the spinal cord
Define motor unit
A motor neurone and all the muscular motor units it innervates
How do lower motor neurones leave the spinal cord?
Anteriorly (ventrally)
Where do upper motor neurones originate?
In the motor region of the cerebral cortex or brainstem
Where does a lower motor neurone terminate?
On a effector (muscle)
What do alpha motor neurones innervate?
Extrafusal muscle fibres (muscle contraction)
What do gamma motor neurones innervate?
Intrafusal muscle fibres (body position, proprioception)
Where is the anterior corticopspinal tract located?
Anterior-Medially to the anterior horn of the grey matter
Which corticospinal tract contains more fibres?
Lateral, compared to anterior
What is the tectospinal tract involved in?
In head turning to visual stimulus (superior colliculus)
What is the function of the vestibulospinal tract?
Maintains balance/an upright head
Where do the cells of the reticulospinal tract originate from?
Cells found in the pons/medulla
What is a function of the reticulospinal tracts?
To facilitate/inhibit the activity of various descending tracts
The rubrospinal tract functions as a less skilled version of which tract?
The lateral corticospinal tract
How are the fibres of the corticospinal tract organised?
Lower extremity located laterally and upper extremity/head located more medially
What is the pattern of supply from the anterior corticospinal tract?
Mainly supplies the side of the body contralateral to the originating brain hemispheres
What do muscle spindles consist of?
Intrafusal muscle fibres
What are skeletal muscles compromised of?
Extrafusal muscle fibres
What is the middle portion of the muscle spindle associated with?
Type 1a afferent sensory nerves. It is contractile while the ends aren’t
What do gamma motor neurones innervate?
Intrafusal (muscle spindles) muscle fibres
What are spindles innervated by?
Gamma motor neurons
What are skeletal muscles innervated by?
Alpha motor neurons
What does muscle spindle activity contribute to following a stroke?
Change in muscle resistance to stretch
What is the function of muscle spindles?
Detect muscle contraction and relaxation
What will afferent impulses from the Golgi tendon organ result in?
Inhibition of alpha motor neurons of the muscle fibres
Where are Golgi tendon organs situated?
At the junction of skeletal muscle and tendon
Where are 1b afferent fibres found and where do they run?
The sensory fibres leading from the Golgi tendon organ to the spinal cord - they run to the anterior horn
How do Golgi tendon organs measure tension?
Using muscle fibres
Where are small receptive fields found?
In areas like the fingers where we have greatest tackle sensitivity
How do cutaneous receptors act?
Some are phasic (rapidly adapt) and some are tonic (slowly adapts)
How do tactile receptors act?
- As transducers
- Show temporal & spatial summation
Where are the cell bodies for skin receptors?
In dorsal root ganglion
What is the dorsal column-medial lemniscal system?
A tract which carries information regarding touch and proprioception sensation from the skin to higher centres
Where does the dorsal column-medial lemniscal system lie?
In the dorsal (ventral) white matter of the spinal cord
Where does decussation of fibres of the dorsal column-medial lemniscal system occur?
In the medulla as the tract ascends to the brain stem
The channel of which type is open more when the neurone is in the resting state?
Potassium
What is the state of the neurone when it is at resting potential?
Has a negative resting potential inside with respect to the outside
What is the numerical figure for the resting membrane potential of neurons?
-70mV inside with respect to the outside
How is the resting membrane potential of neurones governed?
By the permeability of the membrane to potassium ions
How is the concentration gradient of a neurone maintained?
- Transport of potassium ions out
- Transport of sodium ions in
What happens when an action potential of a neurone occurs?
- Na channels open
- Inside becomes more positive with respect to the outside
What occurs during depolarisation of a neurone?
- Na channels close
- K channels open
What is the change of membrane potential throughout an action potential?
-70mV to 30mV
What happens when the membrane potential reaches 30mV?
Na channels close
What is the purpose of the refractory period?
Facilitates propagation of an action potential in one direction only
What doe refractory periods have an effect on?
Effect on the frequency of action potential capable of being produced in a neurone
Where are synaptic clefts found?
Chemical synapses
Where are gap junctions found?
Electrical synapses
Are chemical synapses inhibitory or excitatory?
Either
Where are neurotransmitters synthesised?
In the cell bodies of the chemical synapses
Does CNI have afferent or efferent components?
Afferent
What occurs when there is damaged to CNI?
Anosmia on the ipsilateral side
How does CNI enter the cranial cavity?
Via small holes in the cribriform plate of the ethmoid bone
When is CNI commonly damaged?
In fractures to the anterior cranial fossa
What may patients who have damage to CNI complain of?
Loss of sensation in their nasal septum
How can CNII be tested?
Observing pupillary constriction in response to light. This is due to the pupillary reflex afferent limb.
How does CNII enter the skull?
Via the optic canal
How does CNII first join the opposite CNII?
Within the optic chiasm
What are CNII closely related to?
The lateral geniculate body
What will a lesion affecting the left optic nerve do?
Result in total blindness in the left eye
What structures run through the cavernous sinus?
CNIII, CNIV, CNVI, CNVII and internal carotid artery
Does CNIII carry parasympathetic fibres?
Yes
What will damage of CNIII lead to?
Ptosis of the eyelid on the same side
What will damage to CNVI lead to?
Inability to abduct the affected eye
What will damage to CNIV lead to?
Complain of double vision as they look down
Where is CNV sensory?
In the face
Where is CNV motor?
For mastication
Where do each of the branches of CNV pass through?
- Superior orbital fissure (ophthalmic)
- Rotundum (Maxillary)
- Ovale (Mandibular)
What will damage to CNV result in?
Loss of the blink reflex on the affected side
What does CNVII do?
Supplies taste information to the anterior 2/3 of the tongue
What does CNIX do?
Supplies taste information to the posterior 1/3 of the tongue
Where receives parasympathetic output from CNVII?
The submandibular salivary gland
Where does CNVII exit the skull?
Via the internal auditory meatus
Where does CNVII give sympathetic innervation via?
The superior cervical ganglion
Where is the nucleus of CNVII?
In the tegmentum of the pons
What are the two divisions of the branches of CNVII?
Inside the internal acoustic meatus and outside the skull
What are the branches of CNVII inside the internal acoustic meatus?
Greater petrosal nerve, nerve to stapedius and chorda tympani nerve
What are the branches of CNVII outside the skull?
Posterior auricular nerve
What is CNVIII concerned with?
Hearing and balance
Where does CNVIII exit the cranial cavity?
Via the internal auditory meatus
What happens if CNVIII is diseased?
May cause rapid eye movements
What may a tumour of CNVIII cause?
Paralysis of the muscles of facial expression
What is CNIX responsible for?
Sensory for the posterior 1/3 of the tongue and motor to the stylopharyngess (swallowing and gag reflex)
Does CNIX have parasympathetic fibres?
Yes - they are carried to the parotid glands for scretormotour innervation
Which cranial nerve supplies the muscles of the hypoglossal and pharynx?
CNIX
Where does CNIX leave the cranium?
Through the jugular foramen
Is CNX motor or sensory?
Both
What is CNX motor for?
Laryngeal and pharyngeal muscles
What is CNX parasympathetic function?
To heart, lungs and bowel
At what level does CNX leave the brain?
Level of the medulla
What does CNX cause when stimulated?
Decreased heart rate and blood pressure
Is CNXI motor or sensory?
Purely motor
Does CNXI have a cranial or sensory root?
Both
What does CNXI run in close proximity to?
The internal jugular vein - they exit the internal jugular foramen together
What does injury to CNXI cause?
Paralysis of the sternocleidomastoid and superior trapezius muscles on the same side
What does CNXII supply?
The majority of extrinsic and all intrinsic muscles of the tongue
Is CNXII motor or sensory?
Motor
Where does CNXII leave the cranial cavity?
The hypoglossal canal
Where is CNXII nerve cell bodies located?
Within the medulla
What will damage to CNXII cause?
Paralysis of the ipsilateral half of the tongue
What does the spinothalamic tract carry?
Pain and temperature to the somatosensory cortex
What happens after the fibres of the spinothalamic tract decussate?
Synapse in the thalamus, then project into the neocortex
What is the middle ear?
A air filled chamber which communicates with the nasal cavity; pressure equalisation (valsalva)
What is conductive deafness?
A reduction in the mechanical transmission of sound waves to the oval window
Which nerve gives sensation to the middle ear?
CNIX
What do the chain of the three ossicles in the middle ear have between them?
Synovial joints
What can the stiffness of the ossicular chain be modified by?
The muscles tensor tympani and stapedius
What is the organ of hearing?
The cochlea
Where does the organ of cortisones rest?
On the basilar membrane
How much does the cochlea coil?
Around 2-3 times around the modulus (the central axis of the spiral)
How do sound waves enter the cochlea?
Via the oval window
What is the basic structure of the basilar membrane?
Wider at the apex, narrower at its base
What are the respective parts of the basilar membrane sensitive to?
Base - sensitive to high frequencies & Apex - sensitive to low frequencies
What is the hair structure in the cochlea?
Single row of inner hair cells and 4-5 rows of outer hair cells
What is the function of semi-circular canals?
Detect rotational acceleration and deceleration
What is linear acceleration/deceleration and gravity detected by?
Otolithic organs (utricle and saccule)
How many semi circular canals are there and how are they arranged?
3 on each side, arranged in 3 different planes
What is the link between semi circular canals and movement of the eyes?
The SCCs affect the movement of both the eyes
What can pouring cold water in the external auditory meatus cause?
Convection currents in the semi circular canals and nystagmus
Where do stereo cilia of the utricles and saccule project?
The otolith membrane
What are the utricle and saccule filled with?
Endolymph
What are mossy fibres in the cerebellum?
Axons which are derived from various brainstem nuclei
What is the proposed function of climbing fibres?
Learning new motor action; motor programme determination via mossy fibres
What are Purkinje cells?
Output neurones from the cerebellar cortex which inhibitory
Where does each Purkinje fibre receive input from?
Thousands of parallel fibres
What is basal ganglia involved in?
The initiation of coordinated movement
Which part of the brain compares intended with actual movement?
Cerebellum
Where does the cerebellum principally receive information from?
The vestibular system
What is the peptide hormone which plays a major role in both ovulation and the activity of the interstitial cells of the testis?
LH
What is the peptide hormone formed in the hypothalamus which is necessary for normal spermatogenesis?
Gonadotrophin-releasing hormone
Give two ways how infertility can arise
- Anovulation
- Cervical mucus hostility
When does implantation happen in conception?
After the blastocyst has hatched through the zona pellucid
When does compaction happen in conception?
In the embryo after embryonic genome activation and before blastocyst formation
What is syngamy?
When after fertilisation, male and female pronucleus’ are unified
What are the 2 genes which confer self-renewal and pluripotent in embryonic stem cells?
OCT4 and Nanog
