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Animal Health Hormon
| Term | Definition |
|---|---|
| Homeostatis | Maintaining the body’s internal environment in a steady state despite a wide range of environmental conditions |
| Homeostatic Systems (2 points) | Nervous system Endocrine system |
| Receptor (2 points) | Neuron that senses changes in the environment (stimulus) Sends nerve impulses or chemical signals (inputs) to control centre |
| Control centre (2 points) | -Sets range of values which must be maintained -Evaluates inputs from receptors – Generates output commands/responses – Typically nerve impulses, hormones, chemical signals |
| Effector (2 points) | – Receives signal from control centre – Produces response/effect that changes controlled condition |
| Negative Feedback system | Reverses/counteracts a change caused by a stimulus Minimises/eliminates effects of stimulus Reestablishing homoeostasis |
| Positive feedback systems | Strengthens/reinforces a change caused by a stimulus |
| How does the endocrine system maintains homoeostasis | Regulates activity and growth of target cells in the body Hormones regulate metabolism |
| Hormones (5 points) | Chemical messenger molecules Secreted into circulatory system Communicate regulatory messages Act on distant target cells Present in blood, milk, urine |
| Classes of hormones(5 points) | 1) Peptide -Gonadotropin Releasing Hormone 2)Polypeptides (<100 peptides)- Adrenaline 3)Protein hormones (>100 peptides) - Prolactin 4)Amines (Derived from tyrosine and tryptophan) - Seratonin 5)Steroids(lipophillic) - Testosterone |
| Endocrine glands | Secrete directly into Extracellular fluid and travel via the blood stream (internally) |
| Exocrine glands | Secrete into ducts that empty onto the surface of a covering/lining Eg. Mucus, sweat, oil, earwax, saliva, digestive enzymes |
| Ectocrine signalling | The hormone is secreted in to the environment e.g. pheromones |
| GnRH | Gonadotropin- Hypothalamus- Stimulates FSH, LH release |
| GNRH | Growth Hormone Releaseing Hormone - Hypothalamus- Stimulates GH release |
| Oxytocin | Posterior pituitary- Stimulates utherine contraction, milk let down |
| Glucocorticoids | Adrenal Cortex- Essential for normal response to stress |
| Epinephrine /Norepinephrine | Adrenal Medulla-Augments sympathetic response to stress by actions on several organs |
| Melatonin | Pineal Gland - Regulates sleep |
| Testosterone | Testes - sperm production |
| Oestradiol, progesterone | Ovaries - Stimulates utherine lining |