Anatomy Basics Flashcards
Types of junctions
Adherence, desmosomes, hemidesmosomes, tight junctions and gal junctions
Difference between desmosomes and hemidesmosomes
Hemidesmosomes attack cell to basement membrane while desmosomes attach 1 epithelia to another
Components of extra cellular matrix
Collagen, elastin, adhesive proteins Glycosaminoglycans (forms large hydrated gel)
Layers of the skin
Epidermis, dermis, superficial fascia, deep fascia, serous membrane
2 types of tissue in bone and basic structure
Compact bone: external surface of bones, osteon form the structural unit. Can usually only resist force coming from one direction. Trabecular bone: deep bone, lighter structure with holes but much stronger and can resist force coming from many directions
Isotonic and isometric muscle contraction
Isotonic: muscle changes length during contraction Isometric: muscle doesn’t change length during contraction (e.g. postural muscle)
Motor unit
Sum of all motor end plates innervated by a motor neuron
Role of astrocytes
Maintenance of BBB, structure, growth, scar tissue
Oligodendrocytes role
Myelination
Microglia role
Immune help
Ependymal cells
Line chambers and passage of CSF and produce it
Vertebral levels of sympathetic nervous system
T1-L2
Sympathetic pathway from spinal chord to effector organ
Spinal chord, then they synapse in ganglion in paravertebral trunk. Lost ganglionic neuron to effector 2 types don’t pass by paravertebral trunk: some go to collateral ganglia (unpaired) then to visceral effectors and adrenal medulla has a direct sympathetic fiber with no synapse. It releases neurotransmitters in the blood
Parasympathetic from spinal chord to effector organ and vertebral level
Vertebral level: cranial nerve (vagus, 9th, 7th, 3rd), S2 to S4 Spinal chord: synapse at ganglion close to effector organ: effector organ
Paracrine vs autocrine release of hormones
• Paracrine - Hormones released locally (act on nearby cells) • Autocrine - hormones released locally (act on itself)
3 types of hormones and what they are
- Proteins/ peptides ◦ Can be small peptides (e.g. ADH) ◦ Can be polypeptides (e.g. insulin) ◦ Can be glycoproteins - polypeptides bound to a carbohydrate (e.g. LH). ◦ First synthesised as preprohormones, then proteolytic enzymes cleave them to form prohormones ◦ Water soluble, so have short half lives. ◦ Made in hypothalamus, pituitiary, parathyroid, GI tract and pancreas. 2. Steroids ◦ Structure is 3 6-carbon rings, 1 5-carbon ring. Derived from cholesterol ◦ Fat soluble, transported by proteins like albumin. ◦ Made in mitochondria/ SER. ◦ not stored so release is dependent on synthesis. ◦ produced in adrenal gland and sex organs. (sex hormones and adrenal cortex hormones) 3. Amines ◦ A type of hormone that comes from tyrosine, can be made into 2 main types: ◦ thyroid hormone ‣ lipid soluble, long half life, produced and stored in thyroid gland. ◦ catecholamines ‣ Water soluble so can’t cross membrane, short half life, stored intracellularly in granules (e.g. adrenaline)
How steroid hormones bind to receptors and action
- Hormone enters cell 2. Binds to cytoplasmic or nuclear receptor 3. Hormone-receptor complex moves to nucleus 4. Dimerization: 2 hormone-receptor complexes bind to HRE (hormone response element) of DNA, causing transcription.
How water-soluble hormones bind to receptors and action mechanism
- Binds to one of 3 receptors: A. Monomeric: single unit crosses membrane B. Multimeric: 2 or more crosses membrane (e.g. insulin receptor) C. 7 membrane spanning domain: beta adrenergic for e.g. 2. Binding of hormone causes change in receptor conformation 3. Causes change intracellularly: signaling cascade.
How hormones are released in the anterior lobe of the pituitary gland
Hormones are produced in hypothalamus and are released to the anterior pituitary by the pituitary portal system.
Role of hormones in anterior lobe of pituitary
Hormones produced by this lobe are responsible for regulating endocrine glands downstream in the body (e.g. thyroid). Only 1, prolactin, is not responsible for regulating a downstream hormone.
How hormones are released in the posterior lobe of the pituitary gland (including nuclei).
Hormones are sent from the supraoptic and paraventricular nucleus, travel through the axon and are sent to the bloodstream.
2 mechanisms of control of hormone secretion of pituitary gland.
Hypothalamic hypophysiotrophic hormone secretion Negative feedback from dowstream hormones.
Mesentery
A double fold of the peritoneum which connects the intestines to the abdominal wall.
Difference between Intra peritoneal and retro peritoneal
Intra: completely surrounded by peritoneum Retro: covered partly by the peritoneum
