Cells Flashcards
Which 6 hormones are secreted from anterior pituitary?
FLAT GP
FSH, LH, ACTH, TSH, GH, PTH
What are the 3 mechanisms of hormone release?
Humoral - eg change of Ca in blood stimulates PTH release
Neural - eg adrenal medulla stimulated by SNS
Hormonal - eg hypothalamus secretes releasing hormones to stimulate hormone release from anterior pituitary
Which 2 hormones are secreted from the posterior pituitary?
ADH, oxytocin
Where is the neuroendocrine system?
Glands with predominant endocrine function
Collections of tissues within other specialised organs
Dispersed as single cells i.e. the diffuse neuroendocrine system derived from neural crest cells
Co-production of amine hormone/transmitters, peptide hormone/transmitters
Where are Neuroendocrine cells present as single dispersed cells?
Enteric
Pulmonary
Which cells of the thyroid secrete calcitonin?
C cells
Describe the location of the Neuroendocrine system
Pineal gland Hypothalamus Pituitary gland Thyroid gland Parathyroid glands Adrenal glands Pancreas Gonads
What do Neuroendocrine cells look like?
Lots of vesicles
Nucleus away from the site, prominent nucleolus
Close proximity to neurons
Abundant granular cytoplasm
Why are Neuroendocrine cells particularly important in health and disease?
Can be location of cancers
What are the hallmarks of neuroendocrine cells?
Amine precursor uptake and decarboxylation
Possession of cytoplasmic neurosecretory vesicles
What are the cellular layers of the adrenal gland?
Capsule Zona glomerulosa - secretes aldosterone Zona fasiculata - secretes cortisol Zona reticularis - androgens Adrenal medulla - Neuroendocrine cells, paraganglia
What is pheochromocytoma?
Neuroendocrine tumour of medulla of adrenal gland
Secretes high amounts of catecholamines
Present with sympathetic symptoms
Give examples of Neuroendocrine cells
C cells in thyroid
Juxtaglomerular apparatus
Paraganglia - aortic and carotid bodies
What are carcinoid tumours?
Neuroendocrine tumour
Carcinoid syndrome - collection of symptoms, usually when it has spread to the liver
What controls levels of prolactin?
Dopamine
What is special about the hypothalamic blood supply?
Hypophyseal portal system
Connects it to anterior pituitary
Allows fast communication
What are the roles of Neuroendocrine cells in the enteric system?
Regulate intestinal movements and the release of digestive enzymes
What are the roles of Neuroendocrine cells in the respiratory system?
Developmental stages of the respiratory organs
Regulate respiratory function
Important in lung damage
Describe the Neuroendocrine involvement in hypoglycaemia
Low glucose levels cause signal to hypothalamus, adrenal medulla and pancreas
Hypothalamus leads to increased cortisol to rebuild glucose stores
Adrenal medulla secretes adrenaline which releases stored glucose and decreases utilisation
Pancreas secretes glucagon to promote glucose release from stores
What 5 Factors affecting cellular aging and degeneration?
Genetics Diet Social Age related disease Cellular alterations
What 6 factors can cause cell injury?
Deceased ATP Mitochondrial damage Entry of Ca ROS Membrane damage Protein misfolding DNA damage
What are potential consequences of cellular ageing?
Reduced capacity to function
Reduced capacity to respond to injury
Cell Death
What causes cellular aging?
Exposure to harmful exogenous influences
Cellular and Molecular damage including genetic abnormalities Progressive declinein cellular function and viability
What is replicative senescence?
Decreased cellular replication due to decreasing telomere length
What Changes contribute to cellular aging?
Replicative senescence
Accumulation of metabolic and genetic changes
Reactive Oxygen Species Injure cells
How do Reactive Oxygen Species Injure cells?
Membrane lipid peroxidation
Interaction with proteins
DNA damage
What is the pattern of clinical features of Alzheimer’s disease?
Impaired higher functioning, change in mood and behaviour
Disorientation, memory loss and aphasia
Profound disability and immobility
Death
What pathological changes cause Alzheimer’s?
build up of beta amyloid (Aβ) from amyloid precursor protein (APP)
Alpha secretase precludes AB formation as it cleaves through middle
Beta and gamma secretase lead to AB formation which form plaques
This causes kinase activation which phosphorylates tau
Micro tubules disassemble and form tangles