Labs Flashcards
Rats - teeth
Dentition adapted for gnawing Paired incisors grow throughout life and lack enamel on their posterior surfaces --> rapidly wears --> characteristic chisel-shape Lower jaw (mandible) is in 2 pieces, hinged in the middle Space between incisors can be varied at will
Rats - gall bladder
Absent in rats
Rats - reproductive system vs in humans
Rats:
Female - uterus is Y-shaped
Male - penis mostly within abdominal wall
Humans:
Female - uterus is pear-shaped
Rats - nostrils/nares
May be closed under water
Rats - identifying male vs female
Male:
Scrotum (which contains testes) will be seen near anus
Anterior to scrotum is prepuce (skin fold concealing glans of penis)
Flaccid penis contained within abdominal wall
Female:
Three openings - anus, vaginal opening, urethral opening
Rats - thymus gland is _____ to the heart
Anterior
Rats - when making the first cut and you hit resistance, what have you reached
The diaphragm
Exposes abdominal cavity - not thoraric cavity, which lies anterior to diaphragm and beneath rib cage
Rats - peritoneum
A wet, slippery, thin membrane bonded to the abdominal wall
Surrounds the peritoneal cavity
Rats - Parietal peritoneum, visceral peritoneum and mesentery
Parietal peritoneum (lining abdominal wall) continuous with mesentery (double layer of peritoneum suspending intestine), further continuous with visceral peritoneum (covering intestine)
Rats - ventral cavities
Two pleural cavities (lung)
Pericardial cavity (heart
Peritoneal cavity
Humans vs rats - pericardium
Much thicker, stronger and fibrous in humans
Rats - What are organs wrapped in?
Serous membrane
Rats - Serous fluid
Allows organs to move over each other easily
Rats - parietal vs visceral peritoneum
Parietal: attached to skin
Visceral: attached to organs
Humans - order of digestion
Oesophagus (tube) Stomach (bag) Small intestine (tube) Caecum (bag) Sigmoid colon (tube)
Rats - liver
Large gland
Has both exocrine and endocrine functions
Highly vascularised
Rats - lung colour
Since killed humanely with CO2(g), lungs will appear dark red and blood-filled (haemorrhage)
Normally is a bright pink colour and spongy texture
Rats - heart
Anterior end (‘base’) is overlapped by 2 lobes of the thymus gland
Rats - why is the gut tube convoluted
So it is long, to gain increased SA for absorption and secretion
Rats: Gut - portions
3 tubular portions: oesophagus, small intestine, large intestine
2 sacs: stomach and caecum
Rats: Where do absorption and secretion occur in gut
Everywhere downstream of oesophagus
Secretion occurs in 2 large glands (liver and pancreas) which are derived embryologically from gut lining and shed their secretions into small intestine
Humans and rats: Where is the stomach located
Lies mostly on the left side
Rats: Stomach - greater and lesser curvature
Oesophagus enters part-way along the lesser curvature (from throat through thoraric cavity, dorsal to heart and lungs, to diaphragm)
Rats: Lining of stomach
Divided into 2 distinct types
Anterior and lateral portion:
Has a thin and translucent wall so gut contents often visible
Specialised for food storage
Lining resembles that of oesophagus - no glands and a protective stratified squamous epithelium
Human stomach doesn’t have such a glandless portion compared to rat
Pyloric region (medial and posterior): Glandular and opaque Numerous simple tubular glands release acids and enzymes which break large molecules down (digestion)
Rats: Stomach - pyloric sphincter
Constriction at outlet of stomach
A collar of smooth muscle which controls flow of stomach contents (chyme) into the duodenum
Rats: Small intestine - structure
Rosette structure
Tube of uniform diameter, about 4 body-lengths from inlet to outlet
Irregularly coiled to allow it to fit within abdomen
Attached to dorsal body wall by a transparent mesentery / double layer of peritoneum
Rats: Small intestine - main function
Absorption of small molecules resulting from digestion
Rats: Small intestine - regions
Duodenum (leaving stomach)
Jejunum
Ileum (entering caecum)
Rats: Small intestine - blood vessels
Often shrouded with fat
Fan out through mesentery to supply and drain intestinal wall
Rats: Pancreas - endocrine or exocrine?
Both
Gland releases an alkaline digestive juice containing enzymes into duodenum
Also contains endocrine cells which secrete hormones into bloodstream
Humans vs rats: Pancreas
Both sit close to the greater curvature of stomach
Rat pancreas is a more diffuse organ than human pancreas
Rats: Pancreas - appearance
Made up of small, scattered pink lobules suspended by mesentery
What is the largest gland in the body
Liver
Rats: Liver - function
Both endocrine and exocrine
Performs numerous functions concerned with metabolic regulation and produces bile (bi-product) which contains mainly excretory products
Rats: Liver - bile salts
Aid in digestion and absorption of fats and vitamins
Humans vs rats: Where is bile stored
Humans and other mammals: stored in a gall bladder whose duct joins the bile duct to discharge into the duodenum
Rats: lack a gall bladder, but like humans, pancreatic ducts join hepatic duct to discharge into the duodenum, a short distance downstream of the pyloric sphincter
Rats: Liver - structure
Large size
About 4 lobes
Dark red colour - rich blood supply (vascular)
CT capsule is very thin
Soft, jelly-like texture
Vulnerable to traumatic injury –> severe internal bleeding
Rats: Liver - receiving blood
Receives venous blood from gut wall (via hepatic portal vein)
Receives oxygenated blood from aorta (via hepatic artery)
Rats: Spleen - which system is it part of
NOT part of digestive system
Part of lymphatic system
Rats: Spleen - structure
Dark red
Elongated
Leaf-shaped
Humans vs rats: Spleen
Human spleen more compact than in rat, since it is fist-shaped instead of leaf-shaped
Sits in same position
Rats - appendix
No appendix
Rats: Large intestine - parts
Caecum
Colon
Rectum
Anus
Rats: Large intestine - function
Reabsorption of water
Formation of faeces from undigested food residue
Rats: Large intestine - faeces
Resident bacteria contribute to putrification of faeces
Retained in rectum
Voided periodically through anus
Rats: Caecum - structure
Flabby, thin-walled bag
Contains poop
Humans: Terminates in a vermiform appendix containing lymphoid tissue
Rats: Lack a true vermiform appendix
Rats: Caecum - function
Bacteria act on gut contents while they are slow-moving
Rats: Colon - parts
Ascending (anteriorly) on right
Transverse
Descending (posteriorly) on left towards rectum
Quite untidy arc, much less geometric than human colon
Rats: Colon - firmness
Colonic contents upstream are semi-fluid, but downstream are formed into more or less firm faeces
Rats: Rectum
Short passage leading to anal outlet
Only visible after extensive dissection
Rats: Anus
A sphincter under partial voluntary control
Allows faeces to be voided
Rats: Kidneys - structure
Buried in fat on dorsal wall of abdominal cavity
Ventral surface: covered with parietal peritoneum
Dorsal surface: attached to body wall
Said to be retroperitoneal (behind the peritoneum)
Dark red - rich blood supply
Rats: Kidneys - hilus/depression on medial surface
Point where renal artery, renal vein and ureter access kidney
Rats: Adrenal glands
Small brown bodies embedded in fat near anterior pole of kidneys
Outer crust/cortex: secretes steroid hormones
Inner core (medulla): secretes adrenalin
Rats: Urinary bladder
Midline near pelvis
Pale cream or yellow in colour
Varying in size depending empty or full
Rats: Male reproductive organs - reproductive glands
Seminal vesicles
Prostate gland
Rats: Female reproductive organs - horns
At distal end of each horn is a small dark-coloured ovary which connects via a tightly-coiled oviduct
Oviduct so small it’s difficult to distinguish from ovary
Rats: Female reproductive organs - why is uterus Y-shaped
Multiple babies
Rats: Mouth and pharyx - breathing vs swallowing
Breathing: air must transit from nasal passages to trachea
Swallowing: food must transit from mouth to oesophagus
i.e. food and air must cross over
If coordination lost during swallowing, food may enter trachea –> violent coughing to eject foreign material
Or, air may enter stomach –> eructation (belching)
Rats: Hard palate
Anterior roof of mouth
Body partition separating mouth from nasal cavities
During chewing, food is sorted according to size by rolling it between tongue and hard palate
Rats: Soft palate
Posterior roof of mouth
Lacks core of bone
Rats: Molar teeth
Three molar teeth form a grinding battery on each side of both jaws
Rats: Glottis
Opening into trachea
Rings of cartilage supporting trachea make it easy to identify
Rats: Epiglottis
Ventral to glottis
Triangular flap which closes during swallowing to prevent food or water entering trachea
Rats: Oesophagus
Empty oesophagus is a flattened and transparent tube
Rats: Salivary glands
Shed their secretions into mouth
Colour similar to surrounding CT and muscle
Sheep heart: Venae cavae
Two anterior venae cavae (large right and small left)
One middle posterior venae cava
Which part of the heart forms the apex
Larger left ventricle
Sheep heart: Septum
Separates right and left ventricles
Marks the course of one of the coronary arteries and a cardiac vein
Sheep heart: Atria
Resemble small, collapsed and wrinkled bags
Have little fat –> dark red colour
Sheep heart: Atria - ventral view
Only flabby ear-like auricles visible, as they project from the base of the heart
Sheep heart: Great arteries
Most shrouded with fat
Only one easily seen without dissection - the pulmonary trunk
Sheep heart: Pulmonary trunk
Most ventral of all vessels
Thick, rubbery, cream-coloured wall
Sheep heart: Distinguishing between ventral and dorsal view
- Pulmonary trunk seen in ventral view
- Slanted interventricular sulcus in ventral view, Straighter interventricular sulcus in dorsal view
- Ventral surface is more curved, dorsal surface is flatter
- Auricles always point ventrally
Sheep heart: Great veins
Almost invisible on the real heart because their thin and membranous walls have collapsed after death
Sheep heart: Pulmonary trunk leaves the…
Right ventricle on the ventral side of the heart
Sheep heart: Large white aorta - where
Lies just beneath the pulmonary trunk
Sheep heart: Aorta and pulmonary trunk
Make a half-twist around each other as they leave the heart
Sheep heart: Ligamentum arteriosum
A fibrous bridge linking the pulmonary trunk to the aorta
Sheep heart: Base of heart
Broad end of heart
4 openings into ventricles
Sheep heart: Atria - parts
Each atrium has 2 parts
Main part = smooth internal wall
Second part = atrial appendage / auricle
- irregular surface where bundles of muscle fibres cross each other
Have diff origins in developing embryo
Sheep heart: Atria - structure
Thin-walled
Low pressure
Must get blood into ventricles, so ventricles will lower their pressure for this to happen
Sheep heart: Interventricular septum
Between left and right ventricles
Sheep heart: Tricuspid valve
Three flaps/cusps
Soft and transparent, but strong
Sheep heart: Tricuspid valve - contraction of ventricle
Valve flaps close tgt and are held tightly by chordae tendineae
Sheep heart: Chordae tendineae
Tough CT
White and avascular
Placed in tension by papillary muscles
Sheep heart: Moderator band
Slender bridge, traversing the right ventricle from wall to wall
Made of muscle, not CT
Contains Purkinje fibres
Not involved in contraction, but is conductive
Gives papillary muscle a heads up to brace for incoming AP
Sheep heart: Mitral valve - flaps
Only has 2 flaps, they are correspondingly larger
Sheep heart: Aortic valve
Contains coronary ostia, which are holes which lead to coronary arteries
Sheep heart: Coronary arteries
Compared to major blood vessels, they’re small but obstruction of them has fatal consequences
Sheep heart: Coronary arteries vs cardiac veins
Coronary arteries supply heart
Cardiac veins drain heart of deoxygenated blood
Sheep heart: Cardiac veins
Drain into right atrium
Openings are v small, but can be found along the right atrium
Sheep heart: Fossa ovalis
Found in adult sheep
A translucent membrane that closes the opening
Sheep heart: Fossa ovalis - fetal version
Foramen ovale
Sheep heart: Ligamentum arteriosum - fetal version
Ductus arteriosus
Sheep heart: Before birth (pre-natal)
Secondary oxygen goes from mother to fetus via umbilical cord
Goes from systemic capillaries to right atrium, then right ventricle, but since high resistance of lung (due to being suspended in fluid), little blood goes from RV to lung capillaries –> little blood goes to LA –> LV
So, the foramen ovale allows blood to flow from right to left atrium –> LV
Sheep heart: After birth (post-natal)
Umbilical cord cut off
Baby no longer suspended in fluid –> decreased resistance of lung –> lung capillaries can now inflate
De-ox blood can now go from RV to lung capillaries –> oxygenated –> go to left atrium –> LV
Don’t want oxygenated blood going from LA to RA, so the hole is sealed by growth of CT, forming the fossa ovalis
There is also vasoconstriction of ductus arteriosus –> ligamentum arteriosum
Sheep heart: Trabeculae
Rods
Sheep heart: Visceral pericardium
AKA epicardium
Sheep heart: The heart is shrouded in…
Fat
Sheep heart: Thymus
Glandular structure attached to pericardium
Sheep heart: Blood flows from..
High to low pressure
Sheep heart: Brachiocephalic branch
From aorta
Feeds arms and head/brain
In the sheep heart, blood which enters the coronary arteries has just passed through the..
Aortic valve
Occasionally after the birth of a lamb, the ductus arteriosus fails to close. What is the expected consequence
Greater blood flow to the lungs than to the systemic circuit (lungs at lower pressure)
During dissection of the sheep heart, you used scissors to remove the apex of the heart. What structure was cut?
Papillary muscles
Brain: Poles
The pointy bits of each lobe (e.g. frontal pole is sharper bit of frontal lobe)
Brain: pre-occipital notch
Where the inferior border gradient changes/flattens
Brain: Flow of information when hearing a question and speaking a reply
1° auditory cortex Wernicke's area Arcuate fasciculus Broca's area 1° motor cortex 1° auditory Wernicke's (to make sure you make sense)
Brain: Flow of information when reading a written question and writing a reply
1° visual cortex Supramarginal gyrus Exner's area 1° motor cortex Angular gyrus
Occurrence of unusually high amounts of fat and lipids in faeces of rat most likely due to a problem with…
The liver
What organ manufactures proteins and releases it into the gut and bloodstream
Pancreas
Floor vs roof of midbrain
Floor = cerebral peduncles Roof = colliculi
Rats: Where do hepatic ducts (liver) join the small intestine
Downstream of the pyloric sphincter
Superior and inferior colliculus
Superior - reflexes to sight
Inferior - reflexes to sound
Which hemisphere is Wernicke’s area found in
Left
Sheep heart: What type of artery is the aorta
Elastic artery
Sheep heart: Blood that goes into coronary arteries then goes to…
Cardiac veins –> left anterior vena cava
Male condom
A thin rubber barrier
Fits over erect penis and catches sperm on ejaculation
Best used with water-based lubricant
Helps protect against STIs
Female condom
A thin polyurethane barrier
Goes into the vagina and catches sperm on ejaculation
Helps protect against STIs
Vasectomy
Permanent contraception
Surgical operation
Tubes (vas deferens) cut to stop sperm getting to penis
Tubal ligation
Permanent contraception
Surgical operation
Clips put on tubes (uterine tubes) to stop the egg getting to the uterus
Diaphragm
Fits inside the vagina
Used each time you have sex
Covers the cervix and stops sperm from getting through
Made of silicon and held in place by pelvic muscles
Doesn’t protect against STIs
Hormonal contraception: Combined oral contraceptive pill
Pill made of 2 hormones; oestrogen and progestogen
Stops ovaries releasing an egg each month
Hormonal contraception: Progestogen only pill
Pill made of 1 hormone’ progestogen
Thickens mucous in cervix and may stop ovaries from releasing an egg each month
Intrauterine device (IUD)
Put inside the uterus
2 types - Copper IUD or progestogen-releasing IUD
Stops sperm reaching the egg
Can stay in place for 3 years or more
Depo provera
Hormonal contraception
Injection of progestogen
Stops ovaries from releasing an egg each month
Implant
Progestogen is released from rods put under the skin of arm
Thickening of mucous
May stop ovaries releasing an egg each month
Lung model: Force applied/removed
Force applied to stretch chest wall - lung expands passively
Force removed - lung recoils passively and air is expelled through tube
What is air resistance
The ease with which air can flow through the airways
Lung model: Water manometers
Provide a way to measure pressure in the airway and in the intrapleural space
U-shaped filled with liquid
One end is open to atmosphere (outside arm), other end is open to lung model
Read outside arm
Lung model: Water manometers - pressure change in airway during inspiration and expiration
Inspiration: ~0.1cm down (immediate), then equalises back to 0 (atmospheric)
Expiration: ~0.1 up (immediate), then equalises back to 0 (atmospheric)
Lung model: Water manometers - pressure change in airway during inspiration and expiration with obstructed breathing
Inspiration: ~1cm down, then equalised back to 0
Expiration: ~1cm up, then equalised back to 0
Much greater than without obstructed breathing
Lung model: Water manometers - obstructed vs non-obstructed breathing
No obstruction in airways means more air can travel through it, whereas in obstructed airways, less air can travel through it
With a greater radius in non-obstructed breathing, as you increase V –> increase P gradient –> more air can travel through to equalise faster
Lung model: Water manometers - intrapleural pressure when no active forced applied to chest wall
0 cm H2O
Lung model: Water manometers - intrapleural pressure in lung model vs in humans
In model is 0, but in human lung is subatmospheric (-ve)
Human has outward force (chest wall) and is an enclosed space so P can’t escape –> -ve
Model has no outward force –> 0 force
Lung model: Water manometers - airway vs intrapleural space when holding diaphragm down
Airway: went -ve but v quickly equilibrated back to 0
IP space: went -ve, and remained -ve while held down. Increased V of IP space –> decreased P, and since closed space, air can’t go in –> remains -ve
Lung model: Water manometers - pneumothorax
At rest, deep inspiration and expiration, IP pressure stays at 0 because air is able to move in and out of IP space if P increases or decreases, so lung doesn’t inflate or deflate
Pneumothorax
An injury that allows air to enter the intrapleural space
Lung model: Water manometers - pneumothorax in human lung
F(lung) and F(chest wall) are now uncoupled, so lung can keep on collapsing to the small state, and F of chest wall can cause outer part to keep on collapsing
Lung model: Content inside intrapleural space - model vs real lung
Model: air - expandable
Lung: serous fluid - not easily expandable
Lung model: Estimated V of intrapleural space - model vs real lung
Model: ~1000mL
Lung: ~1mL (negligible)
Lung: Peak flow meters
Used to measure a subject’s peak expiratory flow rate
Lung: Most important factors that contribute to differences in peak flow rates of individuals
Sex and height
Lung: Peak flow rate of an asthmatic vs non-asthmatic
Lower in asthmatic because they have increased R in airways due to bronchoconstriction
Lung: Peak flow rate of young, active smoker vs non-smoking counterpart
Young smoker’s lungs not damaged enough to lower it, but mucous stuck in lung causes cough –> stronger muscles when inspiring –> increased peak flow rate
Lung: Peak flow rate of elderly person smoking for 30 years vs non-smoker counterpart
Smoking causes disruptions of lung tissue and deterioration of elastic fibres –> alveoli collapse and bronchioles constrict –> diseases –> decreased peak flow rate
Lung: Spirometer
An instrument used to measure lung volumes
AKA respirometer
Lung: What can’t spirometers measure
Residual volume and total lung capacity
Lung: Asthmatics - FEV1 and FVC
FEV1 changes (decreases) FVC may not change (from average)
Lung: Dry spirometer - disadvantage(s)
Can’t measure inhalation, e.g. tidal V –> use wet spirometer
Has a time delay –> not ideal for time measurements
Lung: Dry vs wet spirometer - FEV1 values accuracy
Dry would be more accurate as it’s a direct measurement
Lung: Wet spirometer - bell
Inhale = bell moves down Exhale = bell moves up
Musculoskeletal: Proximal vs distal
Proximal: Nearer to point of attachment of a limb or part
Distal: Further away from point of attachment of a limb or part
Musculoskeletal: Origin vs insertion
Origin: A muscle’s attachment to the bone that moves the least during contraction
Insertion: A muscle’s attachment to the bone that moves the most during contraction
Musculoskeletal: Flexion vs extension
Flexion = decrease joint angle Extension = increase joint angle
Chicken leg: Thigh
Tucked alongside torso, so hidden from view
Chicken leg: Leg bones
Large tibia and small fibula
Chicken leg: Tarsals
Proximal foot bones
Chicken leg: Tibiotarsus
A single long bone fused from the leg bones and tarsals, with the fibula remaining as a slender bone partly fused alongside
Chicken leg: Superficial fascia
A soft, weak layer of CT between skin and the deep fascia
Chicken leg: Deep fascia
Thin sheet of CT covering underlying muscle
Chicken leg: Where is the superficial fascia strongest
- Around the intertarsal joint at distal end of leg
- Proximal end of thigh where it joins the pelvis
Chicken leg: Where is the iliofibular muscle found
Beneath the lateral iliotibial muscle
Chicken leg: Iliofibular muscle
Broad at its proximal (pelvic) end
Tapers distally
Chicken leg: What does the tendon of the iliofibular muscle pass through
A CT sling
Chicken leg: What does the sling allow
Allows more contraction of the iliofibular muscle to be converted to movement of the knee and hip joint
Chicken leg: What muscle forms most of the posterior ‘edge’ of the thigh
Lateral knee flexor
Chicken leg: Lateral and medial knee flexor - insertion
Come tgt and share the same insertion
Chicken leg: Parts of the tendon of knee flexor muscles
2 parts;
- Large aponeurosis part (inserts onto tibiotarsus)
- Smaller posterior part (joins a dense fibrous fascia on surface of medial side of shank)
Chicken leg: Lateral knee flexor accessory muscle
Fibres of this muscle run 90° to long axis of thigh
Chicken leg: What movement does contraction of the iliofibular muscle have on chicken hip and knee joint
Hip extension
Knee flexion
Chicken leg: What movement does contraction of the biceps femoris long and short head have on the human hip and knee joint
Long head: hip extension
Short head: no effect on hip joint
Both cause knee flexion
Chicken leg: Tendon of iliofibular muscle - contraction, amplitude and power
Contraction causes a large amplitude movement at knee, with little power because insertion is close to knee
Chicken leg: Synergist vs antagonist muscle
Synergist: aids action of another muscle, e.g. two muscles that cause knee flexion
Antagonist: opposes action of another muscle, e.g. biceps and triceps
Human leg: What compartment does the biceps femoris sit
Within the posterior compartment of the thigh
Human leg: Semimembranosus and semitendinosus
Assist action of biceps femoris - collectively called hamstring muscles
Names are because one is half-tendinous and other is half-membranous
Human leg: Hamstring muscles - biarticulate muscles
Hamstring muscles (except biceps femoris short head) are biarticulate muscles because they cross two joints (hip and knee)
Human leg: How does bending forward at the hip affect the minimum joint angle at the hip when you crouch
Reduces the angle at the hip –> allows more flexion of hip
Human leg: Gait cycle
Right heel strike Right food flat Right mid-stance Right push off Right toe off Right mid-swing
Human leg: Gait cycle - when are the posterior compartment muscles contracting most
- Heel strike
- Foot flat
- Mid-stance
Human leg: Gait cycle - just before heel strike
Hamstrings activated to decelerate swinging limb
Human leg: Gait cycle - heel strike
Hamstrings contract to prevent excessive hip flexion caused by impact of heel strike
Human leg: Gait cycle - mid-stance
Hamstrings activate to extend hip
Human leg: Gait cycle - what are hamstrings trying to do at the knee joint
Contract to slow swinging limb before heel strike and prevent overextension
Wet spirometer: Nomograph
A chart that uses subject’s height and their vital capacity to predict the FEV1.0
What does the wet spirometer measure
It draws out the lung ‘waves’ on a graph paper - you can read off this paper to find the values
