Anatomy and Physiology Flashcards
Main functions of the renal system?
Fluid and electrolyte balance
Removal of waste and reabsorption of others
Regulate blood pH
Endocrine functions
Blood pressure control
Gluco-neogenesis
Regulates blood volume
Regulates RBC production
What is most of the renal medulla made up of?
Pyramids
Main structure of the nephron?
Bowman’s capsule
Glomerulus
Loop of Henle
Vasa recta
Proximal convoluted tubule
Distal convoluted tubule
Collecting duct
What are the two types of nephrons?
Cortical
Juxtamedullary
Differences between cortical and juxtamedullary nephrons?
Cortical: loop of Henle only penetrates outer renal medulla, short loop of Henle, reduced/no vasa recta, small glomeruli, low glomerular filtration rate, 85% of nephrons, excretory/regulatory functions
Juxtamedulla: loop of Henle penetrates deep into medulla, long loop of Henle, large vasa recta, large glomeruli, high glomerular filtration rate, 15% of nephrons, concentrating/diluting urea
How does blood enter the glomerulus?
Afferent arteriole
How does blood leave the glomerulus?
Efferent arteriole
How to calculate urinary excretion rate?
Filtration rate - re-absorption rate + secretion rate
What three processes are involved in renal excretion (urine production)?
Glomerular filtration
Active tubular secretion
Passive tubular re-absorption from tubule
What is glomerular filtration?
Movement of fluid and solutes from the glomerular capillaries into Bowman’s space
What is tubular re-absorption?
Movement of materials from the filtrate in the tubules into the peri-tubular capillaries
What is tubular secretion?
Secretion of solutes from the peri-tubular capillaries into the tubules
Where and how in the nephron is glucose re-absorbed?
Proximal convoluted tubule, ~100%
By two active sodium-dependent glucose transporters (SGLT 1 and 2)
Where and how in the nephron are proteins/amino acids re-absorbed?
Proximal convoluted tubule, ~100%
Active transport
Where in the nephron are vitamins re-absorbed?
Proximal convoluted tubule
Where in the nephron is lactate re-absorbed?
Proximal convoluted tubule
Where in the nephron is creatinine secreted?
Proximal convoluted tubule
Where and how in the nephron is urea re-absorbed/secreted?
Mainly secreted in distal convoluted tubule
Where and how in the nephron is sodium re-absorbed?
65% actively in proximal convoluted tubule
25% actively in thick ascending limb of loop of Henle
5% actively in distal convoluted tubule
5% actively in collecting ducts, stimulated by aldosterone
Where and how in the nephron is chloride re-absorbed?
Symport with sodium in proximal convoluted tubule
By diffusion in ascending loop of Henle and distal convoluted tubule
Symport in collecting ducts
Where and how in the nephron is water re-absorbed?
67% osmotically with solutes in proximal convoluted tubule
15% osmotically in descending limb of loop of Henle
Distal convoluted tubule and collecting ducts by osmosis controlled by ADH
Where and how in the nephron are hydrogen ions secreted?
By diffusion into proximal convoluted tubule
Actively into distal convoluted tubule and collecting ducts
Where and how in the nephron is ammonium secreted?
By diffusion in proximal convoluted tubule, distal convoluted tubule and collecting ducts
Where and how in the nephron is bicarbonate re-absorbed?
80-90% in proximal convoluted tubule symport with sodium
In ascending limb of loop of Henle symport with sodium and antiport with chloride
In collecting ducts antiport with chloride
Where and how in the nephron is potassium re-absorbed and secreted?
65% re absorbed in proximal convoluted tubule by diffusion
20% re absorbed in thick ascending limb of loop of Henle, symport
Actively secreted into distal convoluted tubule
Active secretion controlled by aldosterone in collecting ducts
Where and how in the nephron is calcium re-absorbed?
Proximal convoluted tubule and thick ascending limb of loop of Henle by diffusion
Actively collection ducts if parathyroid hormone present
Where and how in the nephron is magnesium re-absorbed?
By diffusion in proximal convoluted tubule, thick ascending limb of loop of Henle, distal convoluted tubule
Where and how in the nephron is phosphate re-absorbed?
85% by diffusion in proximal convoluted tubule (inhibited by parathyroid hormone)
By diffusion in distal convoluted tubule
Difference between filtrate and plasma?
Filtrate is protein free
Where does the glomerular filtrate need to pass through?
Pores between endothelial cells of the glomerular capillary
Basement membrane
Podocytes
What can be filtered through the glomerular endothelium?
Large pores 70-100 nanometres
Solutes, plasma proteins and fluids
Blood cells cannot pass
Role of the glomerular basement membrane?
Prevents plasma proteins from being filtered out of bloodstream
Role of the glomerular podocytes?
Wrap around capillaries but leave slits, filtration slits, a thin diaphragm between the slits acts as the final filtration barrier
Size of neutral solutes and glomerular filtration?
<180 nanometres freely filtered
>180 <360 nanometres filtered to various degrees
>360 nanometres not freely filtered
How to calculate net filtration pressure?
Hydrostatic pressure of capillary - (colloid osmotic pressure of blood + hydrostatic pressure of bowman’s capsule)
E.g. 55-(15+30) = 10
How to calculate GFR?
Net filtration rate x filtration coefficient (Kf)
What is the filtration coefficient?
Kf
Based on surface area of glomerular capillaries and hydraulic conductivity
What are the three pressures involved in glomerular filtration?
Pgc is glomerular capillary hydrostatic pressure
Pbc is the back pressure built up in the bowman’s capsule
πgc is the colloidal osmotic pressure of the glomerular capillary plasma
What is the tubuloglomerular feedback mechanism?
Involved in autoregulation
Sensed by changes in GFR, renal blood flow and NaCl
Stimulates either relaxation or constriction of afferent arteriole
What is extrinsic regulation of GFR?
Sympathetic nervous system releases norepinephrine-> adrenal medulla releases epinephrine -> leads to constriction of afferent arteriole and inhibition of glomerular filtration
What is renal clearance?
Volume of plasma that is cleared of a specific substance in time unit
Renal clearance calculation?
Renal clearance (RC) = concentration of substance in urine (CU) x flow rate of urine formation (V) / concentration of same substance in plasma (CP)
RC=CUxV/CP
What is creatinine clearance?
To assay the excretory function of the kidneys (ml/min of filtered creatinine). It is a bio marker to estimate GFR
Creatinine clearance formula?
(140-age) x mass in kg x constant
————————————————
Serum creatinine
Male =1.23
Female= 1.04
What is body fluids usually measured in?
Milliosmoles (mom)
What is a milliosmole?
An osmole is an amount of a substance that contributes to the osmotic pressure of a solution. A milliosmole is one-thousandth of an osmole
The solute concentration of body fluids is kept at around….. by the kidneys
300 mom
How do the kidneys keep body fluids at a constant solute concentration?
Counter current mechanism
What is micturition?
Urination
Steps of micturition?
Urine is made in the kidneys.
Urine is stored in the bladder.
The sphincter muscles relax.
The bladder muscle (detrusor) contracts.
The bladder is emptied through the urethra and urine is removed from the body.
What is countercurrent multiplication?
the process of using energy to
generate an osmotic gradient that enables
you to reabsorb water from the tubular
fluid and produce concentrated urine.
Where does the countercurrent multiplication take place?
Loop of Henle, mainly juxtamedullary nephrons
Countercurrent multiplication process?
Step 1: Assume that the Henle loop is filled with a concentration of 300mOsm/L, which is the same as the concentration leaving the proximal tubules.
Step 2: The thick ascending limb of the Henle loop’s active ion pump lowers the concentration inside the tubule and raises the interstitial concentration.
Step 3: Due to osmosis of water out of the descending limb, the tubular fluid in the descending limb and the interstitial fluid quickly approach osmotic equilibrium.
Step 4: Additional fluid flow from the proximal tubule into the Henle loop, causing hyperosmotic fluid previously generated in the descending limb to flow into the ascending limb.
Step 5: More ions are pushed into the interstitium while water remains in the tubular fluid, resulting in a 200-mOsm/L osmotic gradient.
Step 6: As the hyperosmotic tubular fluid from the descending limb flows into the ascending limb, additional solute is constantly pushed out of the tubules and deposited into the medullary interstitium.
Step 7: These stages are repeated over and over, with the net result of bringing more and more solute to the medulla in excess of water. Over time, this process traps solutes in the medulla and magnifies the concentration gradient generated by active pumping of ions out of the thick ascending limb. Eventually raising the interstitial fluid osmolarity to 1200- 1400 mOsm/L .
What happens when blood osmolarity changes?
Neural signal is sent to the hypothalamus to increase or decrease ADH
What is ADH?
Antidiuretic hormone
What detects changes in blood osmolarity?
Osmoreceptors
How does renin angiotensin system work?
Blood volume/sodium levels detected as low -> juxta-glomerular cells stimulated by b1-adrenergic receptors-> releases enzyme called renin -> renin acts on angiotensinogen -> angiotensin I released -> converted to angiotensin II -> map increases -> adrenal cortex releases aldosterone-> increase in both systemic and glomerular hydrostatic pressure
What is normal blood pH?
7.4
How are the kidneys involved in acid/base balance?
Reabsorption of bicarbonate
Excretion of hydrogen ions
What causes altitude sickness?
Decreased oxygen pressure causes increased rate and depth of respiration-> leading to pCO2 levels to drop and respiratory alkalosis to occur -> over time increased bicarbonate excretion causes pH to go back to normal and allowing respiratory rate to increase to compensate for the alkalosis
What hormone helps renal calcium regulation?
Parathyroid hormone
What are the two main types of cells in the nervous system?
Neurons
Glial cells
What are neurons?
Specialised cells in the nervous system for the transmission of signals and communication with each other through chemical synapses
What are glial cells?
Cells in the nervous system that surround and support neurons
What are the three types of glial cells in the central nervous system?
Astrocytes
Oligodendrocytes
Microglia
What are the three types of glial cells in the peripheral nervous system?
Schwann cells
Enteric glial cells
Satellite cells
What is the nervous system split up into?
Central
Peripheral
What is the peripheral nervous system split up into?
Autonomic
Somatic
What is the autonomic nervous system split up into?
Sympathetic
Parasympathetic
Purpose of the somatic nervous system?
consists of nerves that go to the skin and muscles and is involved in conscious activities
Purpose of the autonomic nervous system?
consists of nerves that connect the CNS to the visceral organs such as the heart, stomach, and intestines. It mediates unconscious activities.
What does the sympathetic nervous system do?
role in responding to dangerous or stressful situations.
What does the parasympathetic nervous system do?
controls bodily functions when a person is at rest.
Effects of sympathetic nervous system?
Increase heart rate.
Dilation of the pupils
Secretion of sweat glands
Dilated muscles
Increased alertness
Slowing down or stopping digestion
Relaxation of the bladder
Effects of parasympathetic nervous system?
Salivation: As part of its rest-and-digest function, the PSNS stimulates production of saliva, which contains enzymes to help your food digest.
Lacrimation: ie making tears. Tears keep your eyes lubricated, preserving their delicate tissues.
Urination: The PSNS contracts the bladder, which squeezes it so urine can come out.
Digestion: The PSNS stimulates the release of saliva to promote digestion. It also enacts peristalsis, or the movement of the stomach and intestines, to digest food as well as release bile for the body to digest fats.
Defecation: The PSNS constricts the sphincters in the intestine and moves digested food material down the digestive tract so a person can have a bowel movement.
What neurotransmitter does the parasympathetic nervous system use?
Acetylcholine
What neurotransmitter does the sympathetic nervous system use?
Mainly Noradrenaline
What is the main excitory neurotransmitter of the brain?
Glutamate
What is the main inhibitory neurotransmitter of the brain?
GABA (Gamma-aminobutyric acid)
Astrocyte structure and function?
In central nervous system
Most abundant, versatile and highly branched glial cells
Cling to neurons, synaptic endings, and capillaries
Help maintain the ionic and chemical environment
Microglial structure and function?
In central nervous system
Small, ovoid cells with thorny processes that touch and monitor neurons
Migrate towards injured neurons
Can transform to phagocytose microorganisms and neuronal debris
Oligodendrocyte structure and function?
Branched cells
The processes wrap central nervous system nerves fibres, forming insulating myelin sheaths (thicker nerve fibres)
Ependymal cell structure and function?
Range in shape from squamous to columnar
May be ciliated- cilia beat to circulate cerebrospinal fluid
Line the central cavities of the brain and spinal column
Form permeable barrier between cerebrospinal fluid in cavities and tissue fluid bathing central nervous system cells
What do satellite and Schwann cells do?
Surround neurons in peripheral nervous system, forming myelin
Purpose of the myelin sheath?
myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells
Features of neurons?
Extreme longevity
Usually amitotic
High metabolic rate
All have cell body and one or more processes
What is the axon?
where electrical impulses from the neuron travel away to be received by other neurons
What are dendrites?
tree-like extensions at the beginning of a neuron that help increase the surface area of the cell body. These tiny protrusions receive information from other neurons and transmit electrical stimulation to the soma
Another name for the neuron cell body?
Soma
How is an action potential conducted?
1) neurotransmitter opens ligand-gated channel
2) positive ions (na+) enter cell to make it less negative
3) if net influx is positive and hits threshold potential then voltage-gated sodium channels open
4) influx of sodium ions causes a chain reaction down axon
5) membrane potential reaches +40mv and sodium stops entering
6) k+ voltage-gated channels open and K+ flows out causing membrane potential to become more negative -10mv
7) neuron becomes hyperpolarised due to k+ flowing out and K+/na+ pumps, -75mv
8) all channels close and returns to resting membrane potential -65mv
How does the neuron sheath speed up electrical impulse condition?
Action potential only conducts in gaps in myelin sheath called nodes of Ranvier
Meaning it can ‘skip’ sections
Called saltatory conduction
Picture of action potential graph
What is the resting membrane potential?
~70mv
What are the three connective tissues layers of muscle?
Epimysium
Perimysium
Endomysium
What is the epimysium?
Outermost layer. Irregular dense connective tissue that allows muscle to contract, move independently and maintain its structure. It also separates muscle from nearby organs and tissues
How are muscles attached?
Either directly to other organs or tissues or indirectly by tendons
What is the perimysium?
Middle layer of connective tissue. Organise muscle fibres into bundles
What is the endomysium?
Innermost layer of connective tissue. A thin layer of collagen and reticular fibres, surrounds the extra cellular matrix of the cells and plays a role in transferring force produced by the muscle fibres to the tendons.
What is the sarcomere?
The smallest contractile unit of the muscle fibre.
Contains myofibrils.
Middle of sarcomere called the M-line.
Borders called Z disks
What is the M-line made up of?
Myomesin proteins
What attaches to the M-line?
Myosin
What are the Z disks made up of?
Alpha actin proteins
What attaches to the Z disks?
Actin
What is a muscle fibre?
An individual muscle cell. Each runs the entire length of the muscle
What is the sarcoplasm?
The cytoplasm of the muscle fibre
What are myofibrils?
Contain actin and myosin. Do not extend the full length of the muscle fibre, instead arranged in sarcomeres
What are the three types of muscle tissue?
Skeletal
Cardiac
Smooth
Features of skeletal muscle?
Voluntary
Striated
Multinuclear
Features of cardiac muscle?
Striated
Involuntary
Features of smooth muscle?
Non striated
Involuntary
What is the sarcolemma?
Plasma membrane of the muscle fibre
What colour are I bands?
Light as only thin filaments
What colour are A bands?
Dark as both think and thin filaments
Functions of muscles?
Movement
Body position
Joint support
Generate heat
Control other organs (valves, pupils etc.)
Special characteristics of muscles?
Excitability - respond to stimuli
Contractility- can contract
Extensibility- can stretch
Elasticity - return to original shape
What are thick filaments made of?
Myosin
What are thin filaments made of?
Actin
What is tropomyosin?
A protein strand that stabilised actin
Blocks muscle concentration by blocking the cross-bridge attachment site
What is troponin?
Protein on actin
Promotes contraction
Forms the cross-bridge between actin and myosin
Affected by calcium
Where is the sarcoplasmic reticulum found?
Surrounding myofibrils
What is the sarcoplasmic reticulum?
A specialised smooth endoplasmic reticulum that stores and released calcium
Where is the T tubule found?
It is part of the sarcolemma (muscle fibre plasma membrane)
Function of the T tubule?
Triggers the release of calcium and conducts nerve impulses to sarcomeres
How does the sliding filament model work?
1) part of myosin head it ATPase, this releases energy to tilt myosin head backwards
2) myosin head binds to actin active site, this is cross-bridge formation
3) the myosin head pulls it back to normal position and pulls actin with it, this is the power stroke
4) combines power strokes of all myosin heads leads to the thin filament sliding across the thick filament
5) this causes muscle contraction
Excitation of a muscle cell process?
1) nerve impulse travels from CNS along motor neuron to neuromuscular junction
2) release of acetylcholine in synaptic cleft
3) acetylcholine binds to receptor on sarcolemma
4) sodium rushes into sarcoplasm and produces action potential in sarcolemma which travels down along T-tubules
5) acetylcholine broken down
6) calcium released from sarcoplasmic reticulum and bind to troponin, so myosin binding sites are exposed on actin
What are twitches?
Irregular muscle contraction
Not normal
What is a graded muscle response?
When a muscle contracts with different degrees of force based on certain circumstances e.g. increased frequency of muscle stimulation, increase number of muscle cells being stimulated, increasing muscle tension
What is muscle tone?
the tension in the relaxed muscle
What causes postural muscle tone?
Steady stretch on tendons and attached muscles (protracted muscle contraction)
What causes phasic muscle tone?
Rapid stretching of tendon
What is muscle atrophy?
Wasting away if not stimulated
How is ATP generated for the muscles?
-Creatine phosphate which transfers energy to ATP
- aerobic respiration where glucose is broken down in presence of oxygen
- lactic acid fermentation in which glucose is broken down in absence of oxygen
What causes muscle fatigue?
Lack of oxygen
Low ATP
Lactic acid accumulation
Types of muscle contraction?
Concentric
Eccentric
Isometric
What is concentric muscle contraction?
Muscle fibres shorten
What is eccentric muscle contraction?
Muscle fibres lengthen
What is isometric muscle contraction?
Muscle fibres do not change length
How are muscles attached to bones/connective tissue?
At two points
-origin: an immovable/less movable bone
-insertion: a moveable bone
What do muscles develop from?
Embryonic cells called myoblasts
Can muscles regenerate?
Common in smooth muscle from the stem cell pericyte
Very limited in cardiac and skeletal muscle
Muscle forms what % of body mass?
36% in women
42% in men
Muscle atrophy vs dystrophy?
Atrophy caused by aging, inactivity, malnutrition etc
Dystrophy causes by a genetic disease
Functions of the respiratory system?
Gas exchange
Acid base balance
Phonation
Pulmonary defences and metabolism
Heat and water elimination
Structures of the upper airways?
Nose
Mouth
Pharynx
Functions of the nose and mouth? Respiratory system
Warms, humidifies and traps foreign bodies
Produces mucus
Functions of the pharynx?
Passageway for food and air to the digestive and respiratory systems
Structures of the lower airways?
Larynx
Trachea
Bronchi
Bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Diffusion membranes
Functional cells in the lungs?
Pneumocyte type I and II
Dust cells
What are pneumocyte type I cells?
Simple squamous epithelial where diffusion takes place
What are pneumocyte type II cells?
Secretory cells
Secrete surfactant
What are dust cells?
Alveolar macrophages
What is the purpose of surfactant in the lungs?
Reduce surface tension
Prevent alveolar collapse
How many alveoli are in each lung?
300 million l
Function of alveoli?
Gas exchange
What is the pleural sac?
Two-layered membranous sac
Around each lung
Parietal pleura and visceral pleura
Intrapleural space contains 15ml of intrapleural fluid
Process of inspiration?
Active process of breathing air in
Lung pressure goes below atmospheric pressure due to contraction of the external intercostal muscles and diaphragm
Chest volume increases sucking air into lungs
Process of expiration?
Passive process of breathing air out
Lung pressure increases above atmospheric pressure
Muscles relax
Chest wall is compressed and volume reduced
Pushing air out of lungs
Three pressures involved in ventilation?
Intrapulmonary pressure (757-763 mmHg)
Atmospheric pressure (760 mmHg)
Intrapleural pressure (755 mmHg, always negative to keep lungs inflated)
What causes a pneunothorax?
Puncture of the intrapleural membrane
Air introduced to the space and pressure becomes 0mmHg
Chest wall springs out and lungs collapse
Ventilation definition?
Breathing air in and out
Respiration definition?
Gas exchange through coordination if the cardiovascular and respiratory systems
How can CO2 be transported to the lungs?
Dissolved in solution
Buffered with water as carbonic acid
Bound to haemoglobin as carb-amino-haemoglobin
How is respiration controlled?
The medullary inspiration centre in the brain that generates nerve impulses which stimulate contraction of the diaphragm and external intercostal muscles
What prevents lungs from over-inflating?
The pneumotaxic area in the brain inhibits the inspiration centre preventing muscle contraction
What does the apneustic area do?
Stimulates inspiratory centre and extends the inspiratory muscles contraction
What is tidal volume?
Tidal volume is the amount of air that moves in or out of the lungs with each respiratory cycle. It measures around 500 mL in an average healthy adult male and approximately 400 mL in a healthy female.
What is expiratory reserve volume?
The extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal, quiet expiration.
What is inspiratory reserve volume?
The extra volume of air that can be inspired with maximal effort after reaching the end of a normal, quiet inspiration.
What is residual volume?
Represents the amount of air left in the lungs after forced exhalation
Can be calculated but not directly measured
Average total lung capacity?
6L
What is lung cancer?
Uncontrolled growth of abnormal cells in the lungs
Malignant tumour
What is the main cause of lung cancer?
Smoking
Lung cancer treatment?
Surgery, radiotherapy, chemotherapy
What is bronchitis?
Irreversible bronchio-constriction
Enlargement and overactivity of mucous glands
Hypertrophy and hyperplasia blocks bronchi and lumen or airways
What is emphysema?
Emphysema is a chronic lung condition in which the air sacs (alveoli) may be destroyed, narrowed, collapsed, stretched, or overinflated
What is haemostasis?
Prevention of blood loss by the interaction between vessel wall, platelets, coagulation and fibrinolytic mechanisms
What is a thrombus?
A clot that adheres to the wall of a blood vessel
What is an embolus?
An intravascular clot that floats within the blood
What is an embolism?
An embolism is when a floating clot (embolus) becomes lodged
How is a platelet-fibrin plus formed?
1) blood vessel constricts to reduce blood flow from the injured area
2) platelet plugs form to temporarily seal the leaking small arteries and veins
3) blood coagulates to plug openings in the damaged vessels and wounds to prevent further bleeding
What is primary haemostasis?
Includes vascular construction, platelet activation and formation of a platelet plug
What is secondary haemostasis?
Involves coagulation cascade, control mechanism and fibrinolysis
How is the vessel wall involved in haemostasis?
Vasoconstriction, release of serotonin and thromboxane A contributes towards this
Pathways of platelet activation?
1) exposed collagen triggers the activation and accumulation of platelets
2) exposed tissue factor initiates thrombin generation, which leads to platelet activation
Another name for tissue factor?
von Willebrand factor
What are inactivated precursor clotting factors called?
Zymogens
What factor deficiency is responsible for type A haemophilia?
8
What factor deficiency is responsible for type B haemophilia?
9
What can an arterial blood clot lead to?
MI, ACS, CVA, TIA, stroke
Can mainly causes arterial clots?
Platelets (white clots)
How to prevent arterial thrombosis?
Antiplatelets
What can venous blood clots cause?
DVT, PE
Can mainly causes venous clots?
Stagnation of blood and hypercoagulability (red clots)
What can cause stagnation of blood?
Bed rest
Surgery
Reduced cardiac output
What can cause hypercoagulability?
Surgery
Pregnancy
Oestrogen administration
Malignancy
MI
Coagulation disorders
How to prevent venous clots?
Anticoagulants
Do the nephrons regenerate?
No, decrease by 10% every 10 years after 40
What makes up the glomerular filtration barrier?
Capillary endothelial cells
Basement membrane
Podocytes
What is urinary excretion rate?
Filtration rate - reabsorption rate + secretion rate
What is the only substance that is completely not reabsorbed in the kidneys?
Creatinine
What is CKD?
Irreversible loss of nephrons
Causes of CKD?
AKI
Hypertension
Diabetes
Other kidney diseases
Pre-renal causes of AKI?
Renal artery stenosis
Heart failure
Haemorrhage
Intrarenal causes of AKI?
Glomerular nephritis
Tubular necrosis
Interstitial nephritis
Post-renal causes of AKI?
BPH
kidney stones
Tumours
How can hypertension cause CKD?
Thickening of blood vessels lead to narrowing of the lumen, therefore, less blood flow to nephrons and lower GFR
Cells sense this and release renin which in turn further adds to hypertension
The cycle repeats and leads to glomerular sclerosis and loss of nephrons
How can diabetes cause CKD?
Diabetic nephropathy caused by increased glucose in the blood
What are the four diabetic nephropathy changes?
Mesangial expansion and proliferation
Podocytopathy leading to atrophy
Glomerular basement membrane thickening
Sclerosis
What is glomerular hyperfiltration?
More blood entering functional nephrons when others are lost
Results in sclerosis due to the pressure and loss of the nephron
Cycle repeats
Clinical signs of CKD?
Increase in water and sodium retention leading to hypertension and oedema
Increase in potassium
Metabolic acidosis
Reduction in calcitriol leading to hypocalcaemia and hyperparathyroidism
Hyperphosphataemia
Uraemia leading to neurological symptoms
Anaemia
What is a neuromuscular junction?
Where axon terminal meets muscle fibre
Another name for the afferent division of the peripheral nervous system?
Sensory
Another name for the efferent division of the peripheral nervous system?
Motor
Peripheral neurons that carry information to the spinal cord have their cell bodies in?
The dorsal root ganglia
Peripheral neurons that carry information away from the spinal cord to skeletal muscles have their cell bodies in?
The ventral horn of the spinal cord
Functions of motor neurons?
Carry signals from the spinal cord to the muscles to produce movement
Order of events of an action potential?
1) stimulus-gates ion channels open and membrane slightly depolarises
2) membrane potential increases to -50mv
3) sodium channels open
4) potassium channels open
5) sodium channels close
6) potassium channels close
7) membrane potential returns to -70mv
What are the two phases of the refractory period?
Absolute period
Relative period
What is the absolute refractory period?
Impossible to initiate a second action potential as a number of voltage gated channels are inactivated
What is the relative refractory period?
A stimulus of greater than normal intensity can elicit a response as only some voltage gated channels are inactivated
What is the purpose of the refractory stage?
Prevents action potentials from flowing backwards
Where is the nucleus found in a neuron?
Soma
Where are the mitochondria in a neuron?
In various high energy places
What are the primary input zones of a neuron?
Dendrites
Function of dendritic spines?
Increase the surface area
Axonal transport of proteins occurs along?
Microtubules
Action potential vs local potential?
Where are action potentials first generated and why?
Axon hillock as there are lots of voltage-gated sodium channels
What kind of information is carried by the ventral roots of the spinal cord?
Motor information to muscles
Clusters of cell bodies in CNS are called?
Nuclei
Clusters of cell bodies in PNS are called?
Ganglia
What is the vagus nerve?
a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract.
Another name for the vagus nerve?
Tenth cranial nerve or X cranial nerve
How many cranial nerves are there?
12 pairs
How many spinal nerves are there?
31 pairs
What are spinal nerves?
Nerves that go to and from the spinal cord
What are cranial nerves?
Nerves that go to and from the brain
What do somatic sensory fibres do?
Convey impulses from skin, skeletal muscles and joints to CNS
What do visceral sensory fibres do?
Convey impulses from visceral organs to CNS
What do somatic motor nerve fibres do?
Conduct impulses from CNS to skeletal muscles
What do visceral motor nerve fibres do?
Conduct impulses to smooth muscle, cardiac muscle and glands
Pre vs post ganglionic neurones?
Are post-ganglion nerves myelinated?
No
Are ganglia present in the somatic or autonomic nervous system?
Autonomic
How nerves in cervical spine?
8
How many nerves in thoracic spine?
12
How many nerves in lumbar spine?
5
How many nerves in sacral spine?
5
How many nerves in coccygeal spine?
1
Where are the cell bodies of neurons in the sympathetic nervous system?
Thoracic and lumbar regions
Where are the cell bodies of neurons in the parasympathetic nervous system?
Cranial and sacral regions
Narrow spectrum penicillins?
Pen V
Benpen
Moderate spectrum penicillins?
Amoxicillin
Ampicillin
Narrow spectrum anti-staph penicillins?
Flucloxacillin
Anti-pseudonoma penicillins?
Piperacillin
Which neurons are longer in the sympathetic nervous system?
Post-ganglion neurons
Which neurons are longer in the parasympathetic nervous system?
Pre-ganglion neurons
What neurotransmitter does the parasympathetic nervous system use?
Acetylcholine
What neurotransmitter do sympathetic pre-ganglion neurons use?
Acetylcholine
What neurotransmitter do sympathetic post-ganglion neurons use?
Mainly catecholamines, but some use acetylcholine
How are messages sent to the autonomic nervous system?
Starts at hypothalamus
Goes down spinal cord
Synapses with spinal nuclei
Goes down pre-ganglionic neuron to ganglion
Then goes down post-ganglionic neuron to target cell
What receptors can acetylcholine bind to?
Nicotinic
Muscarinic
