Neurohormones Flashcards
List some endocrine organs of the body
- Hypothalamus
- Pituitary gland
- Thyroid gland
- Parathyroid gland
- Pancreas
- Ovary (females
- Testosterone (Male)
What does the hypothalamus do?
- Thyrotrophin releasing hormone
- Gonadotrophin releasing hormone
- Corticotrophin releasing hormone
- Growth hormone releasing hormone
What does the Pituitary gland secrete?
Anterior pituitary:
- Thyroid stimulating hormone
- Luteinising hormone
- Follicle stimulating hormone
- Growth hormone
Posterior Pituitary:
- Vasopressin
- Oxytocin
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Name the 2 main control systems of the body
- Endocrine system
- Nervous system
Describe features of the Endocrine system
- Mediators travel within blood vessels
- Utilises chemical mediators (Hormones)
- Slow communication
- Effects can be long lasting
Describe features of the nervous system
- Signalling along nerve fibres
- Transmission of electrical impulses
- Fast communication
- Effects are generally short acting
Describe features of a neurohormone
- Produced by specialised nerve cells called neurosecretory cells
- Secreted into the blood
- Have an affect of cells with some distance away
- Can also act as neurotransmitters/autocrine or paracrine messengers
List the different types of hormones?
- Protein & Peptide hormones
- Amino acid derivatives
- Steroid hormones
Give some features of a protein & peptide hormone
- Vary in size
- Can be synthesised as a precursor
- Can be processed prior to secretion
- Can be post Transcriptionally modified
- Can have multiple subunits synthesised independently and assembled
- E.g. FSH, LH, TSH
Give some features of amino acid derivatives as hormones
- Mostly tyrosine derived
- Neurotransmitter that can also act as a hormone
- E.g. Epinephrine, Norepinephrine, Dopamine
Give some features of Steroid hormones
- Steroid is a class of lipids derived from cholesterol
- Include Cortisol, Aldosterone, Testosterone, Progesterone, Oestradiol
What does the hypothalamus contain?
Contains:
- A Hypophyseal nerve tract: Found just before the start of the pituitary gland
- A Hypophyseal portal circulation: In the bulb like area
Describe the anatomy of the hypothalamo-Hypophyseal system
- The pituitary lies in the bone cavity in the sphenoid bone
- The pituitary is connected to the hypothalamus by a stalk
- The hypothalamic hormones are secreted into a Portal vein at the median eminence
- The delivery of these hormones is dependent on an intact pituitary stalk
What would happen if there was damage to the pituitary stalk?
- Any damage of the pituitary stalk will result in failure of gonadal, thyroid and adrenal function
- As well as mis-regulation of growth
What is the problem with these peptides?
They can act as both hormones and as neurotransmitters
- Sometimes the endocrine and neural functions are linked and in others they are not