Hypothalamus regulates the internal environment through the autonomic system. It controls heart beat, temperature, water balance, as well as glandular secretions of pituitary gland.
Pituitary Gland Is connected to hypothalamus by a stalk. ~ 1 cm in diameter and lies just below the hypothalamus. Has two parts: posterior pituitary and anterior pituitary.
Posterior Pituitary Hypothalamus releases products into posterior pituitary where they are stored and will eventually trigger production of hormones. Hypothalamus releases two products – Oxytocin – ADH (Antidiuretic hormone)
Oxytocin Involved in positive feedback stimulates; – uterine muscle contraction – release of milk from mammary glands. – In males, it is associated with sperm transport.
ADH Promotes absorption of water in kidneys 1.Nerve cells in hypothalamus detect concentrated blood; ADH released and kidneys reabsorb water. 2.As blood becomes dilute, ADH is no longer released. 3.What kind of feedback is this?
Anterior Pituitary Neurohormones synthesized in the hypothalamus regulate release of 6 hormones from anterior pituitary
Six Hormones from anterior pituitary Hormones that go to other glands 1.Thyroid-stimulating hormone (TSH) thyroxin. 2.Adrenocorticotropic hormone (ACTH) cortisol. 3.Gonadotropic hormones: (follicle- stimulating hormone [FSH] and luteinizing hormone [LH]) secrete sex hormones.
Hormones with direct effects on body 1.Prolactin (PRL) is produced in quantity only after childbirth 2.Melanocyte-stimulating hormone (MSH) 3.Growth Hormone (GH or somatotropic hormone)
Thyroid Produces 4 hormones 1.T 3 thyroxine 2. T 4 triiodothyronine – Which target all cells of body – Increase metabolic rate 3.Calcitonin – Targets bones – Lowers blood calcium levels
4.PTH (Parathyroid hormone) – Targets kidneys – Increase Calcium uptake in kidneys and intestines, releases calcium from bones
Adrenal Glands On top of kidneys Each has two parts – outer cortex and inner medulla
Inner medulla Produces: Epinephrine and norepinephrine Causes fight of flight response – Blood glucose level rises – Metabolic rate increases – Bronchioles dilate – Breathing rate increases – Blood vessels to digestive tract and skin constrict; those to skeletal muscles dilate – Cardiac muscle contracts more forcefully and heart rate increases
Cortex Produces Cortisol and Aldosterone Cortisol – Breaks down of muscle protein to amino acids – Breaks down fatty acids – Raises blood glucose levels. – Counteracts inflammatory response
Aldosterone Primary target organ is kidney Promotes uptake of Na + to help control low blood pressure
Pancreas Composed of two types of tissue Exocrine tissue produces and secretes digestive enzymes Endocrine tissue called pancreatic islets (of Langerhans) produce insulin and glucagon
All body cells utilize glucose; therefore, its level must be closely regulated. Insulin is secreted when blood glucose level is high
Three actions of insulin 1.Stimulates liver, fat, and muscle cells to take up glucose 2.Stimulates liver and muscles to store glucose as glycogen. 3.Promotes buildup of fats and proteins - inhibits their use as an energy source.
Three types of hormones Peptides Amino acids Lipids
How hormones interact with target cells 1.Amino acids and peptides - bind to receptors on outside of cell (not lipid soluble) 2.(double messenger system) a)Peptide hormones are the first messenger; b)cAMP and calcium are often the second messenger c) sets an enzyme cascade in motion, which produces response
Lipid Soluble Steroids/lipids enter cells by crossing cell membrane (lipid soluble) and bind to receptors on nuclear membrane/envelope Hormone-receptor complex binds to DNA resulting in activation of genes that produce enzymes required for response
Task 1 Design an experiment to show the effects of the removal of the thyroid gland in mice. Identify the physiological characteristics that should be observed and explain how the data should be recorded.
Task 2 Perform the laboratory activities provided to illustrate some aspects of the endocrine system. These may include the following: – microscopic examination of pancreas to distinguish endocrine tissue from digestive enzyme producing – growth of plants in response to hormonal stimulation
Feedback analyse homeostatic phenomena to identify the feedback mechanisms involved (317-2) hypothalamus-pituitary complex include RF (releasing factor), pituitary hormones and target tissues (e.g., TSH on thyroid). ID of Hyperglycemia, p. 400 Effects of Hormones on BloodSugar, p. 401 Hormonal Control of Metamorphosis, pp. 402–3 Hormone Levels During the Menstrual Cycle, p. 404
Task 3 Effects of Hormones on Blood Sugar, p. 401 Task 4 Hormonal Control of Metamorphosis, pp. 402–3 Task 5 Hormone Levels During the Menstrual Cycle, p. 404
Tasks 3 Analyse and interpret the data provided on blood or urine composition. Use it to determine the role of hormones in homeostasis. (317-2)