endocrine Flashcards
list the six functional groups of chemical messenger
Paracrine
Autocrines
Cytokines
neurotransmitters
hormones
neurohormones
describe paracrine
made locally and act on adjancet cells (same tissue organ) they are tranmitted via extracellular fluid.
Describe autocrine
Hormone produced and exerted effects on the same cell- secretory and target cell are the same.
Describe cytokine
(immunohormones) produced by non-gland cells play a key role in the immune system. they travel through the plood into target cell.
Describe neurotransmitters
Used only by nerves to transmit signals they are between two neurons or with a target cell. Adrenaline can also be a neurotransmitter
Describe hormones
Secreted from specialised glands, they are transported via the circulatory system, these can travel long distances around the body. There are two types, a free monroe or a bound to carrier protein.
describe neuro horomones
Secreted by neurosecretory cells (posterior pituitary). The neuron is the secreting cell, it responds to an electrical signal which when received it will release a neurohormone into the blood, this hormone travels to the target cell, they differ from normal neurons, they are over short distances.
list the five diffferent chemical structure categories of chemical messenger
Steroids
Eicosanoids
Amino acids
Protiens and peptides
Amino acids
Descibe amino acid derivates as chemical messangers
systhesis in cyotosol, they can be pracrines, neurotransmitters or hormones
- hydrophobic / lipophillic (mostly)
Describe steroids as chemical messangers
derived from lipd they are crucial for storage, transport, and sginal release and trasmission
- hydrophobic / lipophilic
describe Eiscosanoids as chemical messangers
dervied from lipids, sythesised on demand from membrane phospholipids, they are often used in inflamiation
- hyrodphobic / lipophobic
Describe protein and peptides as chemical messangers
made from short polypeptides or glycoproteins and small proteins. they bind to transmembrane receptors.
- hyrodophilic / lipophobic
describe amino acids as chemical messangers
there are four amino acids that re chemical messengers, all are neuro tranmitters for the CNS.
what is the importance of the hydrophobicity/hydrophilicity of a chemical messenger
Hydrophobicity/ hydrophilicity influences transport, signal production, synthesis, storage and release. These are determined by the chemical structure of the hormone.
Describe the role of receptors in cell to cell communication
Cell receptors are specialised proteins to receive specific messengers (ligans), these are only for indirect communication.
define primary and secondary endocrine organs (giving examples for each)
Primary - organs which primary function is producing hormones or the endocrine system (pituitary gland, thyroid gland, gonads, pancreas and adrenal cortex)
Secondary - organs which are a part of the endocrine system however have other functions as well. (liver, Pineal, Skin, Kidney, Hypothalamus ect)
Explain the difference between exocrine and endocrine glands
Exocrine glands - Releases substances into an external environment (tears, salivary, nipples, digestive, sweat ect.)
Endocrine glands - release substances into capillary beds attached to the gland (inside body) (pituitary gland, thyroid, Adrenal gland, ect)
Explain the role of the hypothalamus and pituitary, and how the hypothalamus is functionally and structurally connected to both parts of the pituitary
The hypothalamus is the central control of hormone secretion as it is the homeostatic feedback creator, it is directly connected by a stalk to the anterior and posterior pituitary glands.
which pituitary gland in connected through nerves directly to the hypothalamus.
The posterior gland is connected via nerves, this provides a fast feedback loop.
list horomnes secreted by the posterior pituitary gland
oxytocin
Antidiuretic hormone (ADH)
list horomnes secreted by the anterior pitutitary gland
Prolactin
Growth hormone
Follicle stimulating hormone (FSH)
Luteinizing hormone (LH)
Thyroid stimulating hormone (TSH)
Melanocyte Stimulating hormone (MSH)
Adrenocorticotropic Hormone (ACTH)
how is the anterior pituitary gland connnected to the hypothalamus
capillary beds that give feedback to the hypothalamus.
describe the effect of prolactin
secretion of milk
describe the effect of growth hormone
grows the muscle or bone
describe the effect of MSH
skin pigmentation and hunger
describe the effect of FSH
ovulation and spermatogenesis
describe the effect of TSH
stimulates the production of T4 thyroxine or T3 (80%), and triiodothyronine
describe the effect of LH
Triggers the menstrual cycle and testosterone.
describe the effect of oxytocin
love hormone, produces good emotions and birth and milk secretion.
describe the effect of ACTH
regulates cortisol and androgen production (stress and adrenaline) these dilate pupils, increase vasopressin (Blood flow) and decreases pain.
describe the effect of ADH
regulates water reabsorption in the kidneys.
describe agonsit hormones
ligand binds to the receptor which causes a response
describe antagonistic hormones
ligand binds to a receptor that stops a response.
describe synergistic hormones
when two or more hormones both contribute to a single act, these results in a stronger effect than an individual hormone causes.
List the main hormones secreted by the pancreas that are involved in glucose regulation, state what cells they are produced in, and detail their modes of action
Glucagon - produced in the pancreas it increases glycogenolysis, gluconeogenesis and ketogenesis
Insulin - produced in the pancreas it increases protein, fat and glycogen synthesis and glucose oxidation.
list the regions of the adrenal gland and what each segment produces
Zona Glomerulosa - aldosterone (Na+/K+)
Zona Fasciculata - glucocorticoids
Zona Reticularis - sex hormones
Adrenal medulla - Catecholamines
list the two layers of the adrenal gland
Cortex (capsule, Zona glomerulosa, Zona Fasciculata, Zona reticularis)
Adrenal Medulla
list hormones secreted by the thyroid and what they do
Tetraiodothyronine (T4 or thyroxine) - regulation of glucose (energy) consumption
Calcitonin - secreted by C cells
Triiodothyronine (T3) - endochondral growth and foetal growth
Parathyroid hormone (PTH) - regulator of blood /bone calcium levels
describe why the thyroid hormone synthesis is unique
the hormones are stored inactive extracellularly in follicles. (stored in C cells)
Describe the HPA axes
hypothalamic-pituitary-adrenal
When under stress the hypothalamus releases Corticotropin-releasing hormone, this stimulates the anterior pituitary to produce ACTH into the adrenal cortex.
- ACTH produces Mineralocorticoids and Glucocorticoids (these increase nutrient retention in blood and increase BP and blood volume
The hypothalamus also stimulates the adrenal medulla via the preganglionic sympathetic fibre to make Catecholamines
- Catecholamines increase HR, BP, glucose production and metabolic rate, ect.
Describe the HPT axes
When under stressful conditions the hypothalamus releases thyrotropin releasing hormone (TRH) into the anterior pituitary gland.
This stimulates thyroid stimulating hormone which stimulates T3 and T4
The production of these produce a negative feedback for the anterior pituitary.
- The Effects of these include: increase metabolism, cardiac output, Respiration rate, skin and hair growth. This process is crucial for metamorphosis in amphibians
Which hormone can be used to increase milk production in dairy cattle?
Somatotropin
what do Epinephrine and norepinephrine
A generalized vasoconstrictor effect
