Question | Answer |
What are the two principle regions of the breast? | Body and axillary tail |
What connects each lobule inside the breast? | Ducts |
What lies inside each duct? | Alveoli (hollow sacs) |
What fills the spaces around lobules and ducts of the breast? | Fat, ligaments and dense irregular connective tissue |
What is the areola? | A circular, coloured zone that surrounds the nipple |
What triggers the milk ejaculation reflex when infants are nursing? | Stimulation of sensory nerve fibres |
What do areolar glad secretions do? | Protect the area from chapping and cracking when an infant is in nursery |
How is breast size determined? | The amount of adipose tissue |
What attaches the breast to the overlying skin and to the fascia of pectoralis major? | Suspensory ligaments |
When do mammary glands develop? | During pregnancy |
What are the 15-20 lobules of mammary gland separated by? | Stroma |
What drains each lobes? | A lactiferous duct (these dilate to form a lactiferous sinus) |
What are the four quadrants of the breast? | Superior lateral, superior medial, inferior lateral and inferior medial |
Which arteries supply the breast? | Lateral (mammary) thoracic artery, Internal (mammary) thoracic artery, Intercostal artery, Thoracoaeromial |
Which vein drains the breast? | Cephalic vein |
Which nerves innervate the breast? | Medial pectoral nerve, lateral pectoral nerve, long thoracic nerve |
What is the medial boundary of the breast? | Sternum |
What is the lateral boundary of the breast? | Axilla (latissimus dorsi) |
What is the superior boundary of the breast? | Clavicle |
What is the inferior boundary of the breast? | Intramammory crease |
What are the boundaries of the apex? | Outer border of first ribs, superior border of the scapula, posterior border of the clavicle |
What forms the base of the axilla? | Skin |
What forms the anterior wall of the axilla? | Pectoralis major, pectoralis minor and subclavius |
What muscles form the posterior wall of the axilla? | Subscapularis (above) and teres major and latissumus dorsi(below) |
What forms the medial wall of the axilla? | Serratus anterior and the ribcage |
What forms the lateral wall of the axilla? | Intertubercular sulcus (Coracobrachialis and short head of biceps brachii) |
Describe the arterial blood supply of the superior limb | Subcalvian artery provides blood to arm. At lateral border of the 1st rib it enters the axilla and now axillary artery. Leaves axilla at lower border of teres major, continues as the brachial artery. Splits into radial and ulna arteries at cubital fossa |
Which artery supplies blood to the upper limb? | Subclavian artery |
Where does the brachial artery split into the radial and ulna arteries? | Cubital fossa |
What do the paired brachial veins unite to form? | A single axillary vein |
Where des the axillary vein pass through before it becomes the subclavian vein? | The axilla, at the lateral border of the first rib |
Approximately how many lymph nodes are there in the axillary region? | 20-30 |
What groups are split into? | Anterior (pectoral), posterior (subscapular), lateral (brachial), central, infraclavicular and apical |
Where do the efferent vessels of these axillary lymph nodes drain into? | Subclavian lymphatic trunk |
What is cell proliferation? | An increase in the number of cells as a result of cell growth and cell division |
How is the mitotic rate of a cell controlled? | Activating or deactivatin genes that promote division (eg p53). The level of maturation-promoting factor/M-phase promoting (MPF) |
What two parts if M-phase promoting factor (MPF) assembled from? | A cell division cycle protein called Cdc2 and a second protein called cyclin |
What are genes that inhibit cell division called? Give an example | Repressor genes e.g. p53 |
What is atrophy? | The shrinkage of a tissue through a loss in cell size and number |
What is senile atrophy? | Atrophy caused by normal aging |
What is disuse atrophy? | Atrophy caused by the lack of use of an organ |
What is necrosis? | The premature, pathological death of tissue due to trauma, toxins, infection etc |
What is infarction? | The sudden death of a tissue caused when its blood supply is cut |
What is Fas? | A receptor in the plasma membranes of cells that extracellular suicide cells bind to |
What happens when Fas is activated? | Intracellular enzymes such as endonuclease and protease, are activated to destroy the cell |
Where is the intrinsic apoptosis pathway activated from? | From within the cell |
When might this pathway be activated? | In response to signals resulting from DNA damage, loss of cell-survival factors or other types of severe cell stress |
What must be released to trigger this pathway? | Pro-apoptotic signals |
Whch family of proteins determine whether a pro- or anti- apoptotic cell signal will be released from the cell? | BcI-2 family |
Describe the process of the triggering of the intrinsic apoptosis pathway? | -Anti-apoptotic proteins (eg Bcl-Xl) antagonise Bax and Bak by binding to their BH3 domains
-BH3-only proapoptotic proteins alternatively bind to anti-apoptotic proteins like Bcl-Xl
-Usually cellular stress would result in an up-regulation of BH3-only |
Describe the intrinsic apoptosis pathway | p53> mitochondria> cytochrome C> apaf-1> apoptosome> capsase 9> capsases 3 & 7> apoptosis |
Where and how does the extrinsic apoptosis pathway begin? | Outside the cell as pro-apoptotic receptors on the cell surface are activated by pro-apoptotic ligands |
What do clusters of pro-apoptotic ligands form? | Death Inducing Signalling Complex (DISC) |
What happens upon DISC activation? | Extrinsic pathway adops the same capsase mechanism as the intrinsic apoptotic pathway |
In mitosis, what causes A) Chromosome condensation B) spindle formation C) nuclear envelope breakdown? | A) Phosphorylation of Histone 1
B) Phosphorylation of MAP
C) Phosphorylation of Lamin |
what does HER2 signalling induce? | Cyclin D1 expression |
What regulates progression through the cell cycle? | Cyclin/CDK complexes |
What does overexpression of HER2 lead to in breast cancer? | Cyclin D1 formation which results in cell devision and tumour formation |