Week 11- Endocrine System Flashcards
What is the endocrine system
Chemical messenger (hormones) system within the human body that maintains the constant internal environment of the human body (homeostasis)
Name endocrine organs in the brain
Pineal gland
Hypothalamus
Pituitary gland
Name endocrine organs in the throat
Thyroid
Parathymoid
Thymus
Name endocrine organs in the upper abdomen
Adrenal cortex
Kidney
Pancreas
Name endocrine organs in the lower abdomen
Testes (male)
Ovaries (female)
Uterus (female)
How are hormones activated
Change in the local environment
Low circulation of ions or nutrients (hum oral control)
Response to stress, anxiety (fight or flight)
Describe 2 ways in which hormones can alter the function of a target cell
1) bind to a receptor on the outside of a cell (G-protein coupled) that implements a sequence of reactions inside the cell that dictate a certain action/function
2) enter the cell and instigate a change in a receptor in the nucleus causing a shift in proteins being created by the cell, which can alter cell function (steroid hormones)
Describe fully the binding to a hormone on the outside of a cell
-hormone attatches to actioned site of the receptor
-triggers a release of G-protein
-this activates ADENYL CYCLASE which convert ATP into CYCLIC AMP
-cyclic AMP activates protein KINASE A (PKA)
-PKA can then phosphorylate a protein within the cell that can start a signal (activate/inhibit) causing a mechanism within the cell to change
Describe fully the binding to a hormone on the inside of a cell
-steroid hormones is lipid soluble so can pass into cytoplasmof the cell
-it can bind to a receptor and in its activated form enters nucleus of the cell
-this receptor-hormone complex can initiate a change in the transcription of new proteins from the DNA at a specific ‘hormone response elements’
-the newly transcribed mRNA will exit the nucleus and travel to ribosome for translation
- a new protein will be synthesised that can alter cell
Describe the interplay between endocrine system and nervous system
-nervous signals in the brain stimulate the secretion of hormones
-this happens at hypothalamus which activates pituitary gland
-this ‘master gland’ can stimulate other glands of endocrine system
-such as: hypothalamic-pituitary-adrenal (HPA) AXIS
-hypothalamic-pituitary-thyroid (HPT) axis
-hypothalamic-pituitary-gondal (HPG) AXIS
-hypothalamic-pituitary- prolactin (HPP) AXIS
-comminucation In the anterior pituitary is via the hypothalamic hypophyses portal system
Describe Hormones from testes
Testosterone, released from testes
Anabolic- promote tissue building and nutrient storage
Androgenic- promotes masculine characterisations
Describe Hormones from ovaries
Oestrogen and progesterone released from ovaries
Establish and maintain reproductive function
Controls phases of menstrual cycle
Anabolism definition
Biochemical process in METABOLISM where simple molecules combine to generate complex molecules. Requires energy.
Androgen definition
Any group of hormones that’s primarily influence growth and development of male reproductive system
-dominant hormone is testosterone
Describe POLYSISTIC OVARY SYNDROME (pcos)
Overproduction of androgens interfere with developments of eggs and their release from female ovaries. PCOS is a leading cause of infertility.
Describe HYPERTHYROIDISM
Thyroid gland produces too much thyroid hormone
Leads to weigh loss, fast HR, sweating and nervousness
Define HYPOTHYROIDISM
Thyroid gland doesn’t produce enough thyroid hormone
Leads to fatigue
Constipation
Dry skin
Depression
Under active gland can cause slow development in children
Describe type 1 diabetes
Autoimmune in origin
-Body attacks beta cells of pancreas.
-over time, pancreas loses all insulin producing cells
-patient becomes fully reliant on synthetic insulin to manage blood glucose
What does the pancreas secrete
Glucagon
Insulin
Describe pancreas secretion of hormones
GLUCAGON- alpha cells, promote breakdown of glycogen into glucose, promotes G;UCOGENESIS
INSULIN- beta cells, promote cellular uptake and storage of glucose and formation of glycogen
Describe how the anterior pituitary is stimulated and the process which follows
-hypothalamus sends hormones through hypothalamic-hypophyses portal system, stimulating the release
-this hormone sent is a RELEASING HORMONE as it signals the anterior pituatory to start producing hormones.
-the hormone from pituitary entering systemic circulation is then a STIMULATING hormone as it travels to the sites of action
-posterior pituitary doesn’t contain secretory cells. It stores hormones produced by hypothalamus ready for release into circulation when the signal arrives.