Functional Anatomy and Embryology Flashcards
What are the different shapes of epithelial tissue and their examples?
Squamous: capillaries, glomeruli, alveoli
Cuboidal: organs of secretion (thyroid follicles, salivary glands, kidney tubules)
Columnar: digestive tract, uterus
What are the different layer structures of epithelial tissue and their examples?
Simple: blood vessels
Pseudostratified: trachea
Stratified: cornea
What are the different surface specialisations of epithelial tissue and their examples?
Ciliated: airways
Brush border (microvilli): gut
Keratinized: skin
What are the three mechanisms of exocrine secretion?
Merocrine: exocytosis (salivary glands)
Apocrine: part of the apical cytoplasm of the cell is lost (sweat glands, mammary glands, prostate)
Holocrine: breakdown and discharge of the entire secretory cell (sebaceous glands)
What is the structure of tight junctions?
Non-anchoring, seal inter membrane space (occludin and claudin)
What is the structure of desmosomes and hemidesmosomes?
Anchoring;
Cytoskeletal IF: keratin
Linker protein complex/anchor protein: plakoglobin, desmoplankin
Adhesion proteins: cadherin family (homophillic proteins)
What is the structure of adherence junctions?
Anchoring, concerned with cell shape;
Actin filaments
Anchor proteins: catenins, p120
Cadherin dimers (require calcium)
What is the structure of gap junctions?
1 channel = 6 connexins –> 1 connexon
Allow passage of small peptide up to 10aa, glucose, ATP, O2
What are the three types of connective tissue?
Soft, semi-hard (cartilage) and hard (bone)
What are the types of soft connective tissue?
Mesenchyme: embryonic Loose (areolar): mesentery, papillary dermis Dense: tendon, reticular dermis Reticular: bone marrow, lymph nodes Adipose: fat cells
What is ECM composed of?
Proteins: glycoproteins
- collagen, elastin, adhesive
Glycosaminoglycans (GAGs)
What are the fibrillar and sheet collagen types?
Fibrillar: Type I - skin, bone, tendons, dentine Type II - cartilage Type III - blood vessels, skin Sheet: Type IV - basement membrane
What are elastic fibres composed of?
Network of fibrillin microfibrils embedded in a core of cross-linked elastin
What are adhesive proteins?
Cross-link cells of CT with collagen, bind to integrins
Fibronectin, tenascin (produced at wounds), laminin
What are GAGs?
sugar polymers - repeating units of disaccharides, draw water due to negative ionic charge forming porous hydrated gel –> allow ECM to withstand compressive forces
What are proteoglycans?
GAGs attached to proteins through link proteins
What are the indigenous cells of CT?
Mesenchymal stem cells: fibroblasts, adipocytes, mast cells
What are the immigrant cells of CT?
Neutrophils, monocytes/macrophages, dendritic cells, eosinophils, basophils, lymphocytes
What is the epidermis composed of?
Keratinocytes (90%)
Melanocytes
Langerhan cells
Merkel cells
What does the superficial fascia contain, where is it found and what are its functions?
collagen, elastic fibers and varying amount of fat; just beneath the dermis
storage of water and fat, conduction, protection against mechanical shock, thermal insulation
What is the deep fascia composed of and what are its functions?
highly organised connective tissue layer, contains little fat
conduction, movement of muscle, attachment for some muscles, capsules around organs and glands
Where does the thoracic duct drain?
Left brachiocephalic vein between left internal jugular and subclavian
What is cartilage composed of?
chondroblasts which secrete ground substance and collagen to form a rigid gel. Chondroblasts become chondrocytes once formed.
No neurovascular elements
What is foetal skeleton formed by?
Hyaline cartilage
Where in the bone is red bone marrow contained?
In the trabecular/spongy bone
Where in the bone is yellow bone marrow contained?
In the medullary cavity
What is endochondral ossification?
When bone develops by replacing hyaline cartilage
Primary ossification centre: along the diaphysis
Secondary ossification centre: in epiphysis
What is intramembranous ossification?
When compact and spongy bone develop directly from sheets of mesenchymal connective tissue.
How is an osteon arranged?
Osteocytes are arranged in concentric layers around a central (Haversian) canal containing blood vessels
What are the three types of joints?
Fibrous (united by collagen): sutures, syndesmoses, gomphoses;
Cartilaginous (united by cartilage): synchondroses, symphyses;
Synovial (fluid filled cavity, separates skeletal elements which are united by a fibrous capsule)
What is isometric and isotonic contraction?
Isometric: muscle exerts force without changing length
Isotonic: concentric - muscle shortens during force production (eccentric: muscle produces force but length increases)
What are the layers of connective tissue that hold muscle fibres in position in skeletal muscle?
Epimysium: surrounds entire muscle
Perimysium: surrounds bundles of muscle fibres to form fascicles
Endomysium: surrounds each muscle fibre within fasciculus
What is the myotendinous junction?
Where endo, peri and epimysium merge with the dense collagenous connective tissue of the tendon
How does skeletal muscle form?
Myoblasts fuse into myotubes (immature muscle fibers)
Muscle fibres contain satellite cells on the surface –> can provide new myonuclei
What are myofibrils composed of?
Myosin and actin filaments; divided into sarcomeres
What are the different bands and zones of a sarcomere?
A band: whole myosin part with overlap
I band: where you find only actin
H band/zone: only myosin
Z lines: delimit the sarcomere (alpha-actinin and desmin)
What are the different sub-types of muscle fibres?
Slow myosin isoform: found in red muscle fibres, contain a lot of myoglobin
Fast myosin isoform: found in white muscle fibres, contain small amounts of myoglobin
Type I slow: oxidative
Type IIa: fast oxidative
Type IIb: fast glycolytic
Type IIx: super fast glycolytic
What is Duchenne muscular dystrophy?
Loss of dystrophin (helps link contractile apparatus to ECM)
X-linked recessive
What factors drive a precursor cell to undergo terminal differentiation to form a muscle cell?
Myogenic regulatory factors
What is the function of astrocytes?
Maintenance of blood-brain barrier, structural strength to CNS, produce scar tissue, direct neuronal growth development, control interstitial environments (NT recycling)
What is the function of microglia?
Similar function to macrophages and monocytes; remove cell debris, wastes and pathogens by phagocytosis
What is the function of ependymal cells?
Line CSF cavities, probably monitor composition of CSF
What is the function of oligodendrocytes?
Form myelin sheaths around neuronal axons in CNS
What are satellite cells of the peripheral nervous system?
Surround neuron cell bodies in ganglia; control O2, CO2, NT and nutrient levels around it
What type of neurons are in the sensory ganglia?
Pseudo unipolar
What type of neurons are in motor autonomic cells?
Multipolar
Where do nerves of the sympathetic ANS arise from?
T1-L2
Where do nerves of the parasympathetic ANS arise from?
CN III, VII, IX, X
Sacral spinal nerves S2-4
What are the NTs and receptors in the sympathetic and parasympathetic ANS?
Sympathetic: Ach to N, NorEpi to alpha or beta (Ach to M in sweat glands)
Parasympathetic: Ach to N, Ach to M
What is image resolution?
The number of pixels along each axis
What is intensity/grey-scale resolution?
The range of possible intensity values
What is spatial resolution?
The measure of the smallest discernible detail in an image
What is the aspect ratio of an image?
Width/height
What does ‘n bit image’ mean?
means 2^n different intensity values
What is the most common format for medical imaging?
DICOM; non-compressed
Order the following from least to most attenuating material: bone, air, metal, fat, soft tissue/water
air, fat, soft tissue/water, bone, metal
What is CT?
Computed tomography; x-ray projections at many different angles
What is the principle behind PET?
Positron emission tomography;
Inject isotope, emit particle (positron and gamma photons), detect particle
Most commonly used: fluoro-deoxyglucose
What is the principle of nuclear magnetic resonance?
Sample is placed in strong magnetic field
Irradiated with radio waves at resonance frequency
Re-emission of radio waves
Beauty is in the level of differentiation of soft tissue, bone doesn’t show up
What is the principle of US?
Emit short ultrasound waves, listen to what is reflected back
What layers does the abdomen have?
Skin is thin
Superficial fascia is thick
Deep fascia is thin/absent
Epimysium covers the muscles
Which are the retroperitoneal organs?
Suprarenal glands Aorta Duodenum (second and third segments) Pancreas Ureters Colon (ascending and descending) Kidneys Esophagus Rectum
What type of superficial fascia is present in the abdomen?
Camper’s fascia: thick layer formed of fat
Scarpa’s fascia: membranous layer, only present beneath umbilicus
Where is extra-peritoneal fat thickest?
Posteriorly
What are the superficial veins of the abdomen above and below the umbilicus?
Above: paraumbilical, thoracoepigastric (thoracoabdominal), lateral thoracic
Below: superficial epigastric (from femoral vein), superficial circumflex iliac
Which nerves supply rectus abdominis, external oblique and the skin above them?
intercostal nerves T7-T12
Which nerves supply internal oblique and transversus abdominis?
T7-L1
What is the conjoint tendon?
Joins internal oblique and transversus abdominis onto the pubic crest
What is the arcuate line?
1/2 the distance between umbilicus and pubic crest
Above arcuate line: anterior rectus sheath includes EO aponeurosis and anterior lamina of IO, posterior rectus sheath includes posterior lamina of IO and transversus abdominis aponeurosis
Below arcuate line: rectus sheath is all anterior
What are the cutaneous nerves of the pubic area and where do they arise from?
Iliohypogastric (L1) and ilioinguinal (L1)
What are the arteries of the abdominal wall?
Internal thoracic artery –> musculophrenic artery + superior epigastric
Posterior intercostal arteries, anterior intercostal arteries
Lumbar arteries
Inferior epigastric (from external iliac)
What is a hernia?
A protrusion of the parietal peritoneum; it doesn’t have to include organs
What are the positions of inguinal and femoral hernias?
Inguinal: above and medial to pubic tubercle
Femoral: below inguinal ligament and lateral to pubic tubercle
What are the boundaries of the superficial inguinal ring?
medial and lateral crura, external oblique aponeurotic tendon
What is the position of the deep inguinal ring?
one finger breadth above midpoint of inguinal ligament, lateral to inferior epigastric artery
What are the layers within the spermatic cord?
Tunica vaginalis: visceral and parietal (from peritoneum)
Internal spermatic fascia (from transversalis fascia)
Cremasteric fascia + cremaster (from internal oblique)
External spermatic fascia (from external oblique)
Dartos fascia (from Scarpa’s fascia)
What are the boundaries of the inguinal triangle?
Inferior epigastric vessels, linea semilunaris and inguinal ligament
What is the difference between direct and indirect inguinal hernias?
Indirect: protrusion of peritoneum through inguinal canal
Direct: protrusion through external ring, bypassing internal ring
What does the vitelline duct become?
Umbilical cord
Which are the foregut structures?
Pharynx and oesophagus Lower respiratory tract Stomach Duodenum (proximal to bile duct opening) Liver Pancreas Biliary system