Endocrine System Intro PDF

Today’s Outline Topic: Endocrine System Class Outline: - Quiz 2: Nervous System - start intro notes Today’s Assigned Work: - Quiz - Intro notes Upcoming Assignments: - Today’s Outline Topic: Endocrine System Class Outline: - Cow eye lab report? - questions from last week? - Concept check on qu...

Today’s Outline Topic: Endocrine System Class Outline: - Quiz 2: Nervous System - start intro notes Today’s Assigned Work: - Quiz - Intro notes Upcoming Assignments: - Today’s Outline Topic: Endocrine System Class Outline: - Cow eye lab report? - questions from last week? - Concept check on questions from last week - gland group research Today’s Assigned Work: - probe - research glands Upcoming Assignments: - Endocrine System Biology 12  Regulates the body’s daily rhythms and functions Growth rate, hunger, body temperature… Maintains homeostasis by controlling release of hormones Endocrine System  A process by which a constant internal environment is maintained during changes in the external environment. Maintain – continued Constant – the same Internal – inside the body Environment – all around the body What is homeostasis?  Body temperature Blood pressure blood pH Concentrations of O2 and CO2 Osmoregulation (water balance) Blood sugar (blood glucose concentration) What things in your body need to be kept within certain limits?  All organ systems work together to achieve homeostasis. The body has mechanisms to return to these normal limits: Negative feedback Positive feedback The endocrine system and the nervous system are the most important and often work together to maintain homeostasis. How does it work? Nervous System Works by means of electrical impulses in nerve fibres, transmitting messages between various parts of the body and the brain. This system reacts quickly and directs messages to specific places in the body for reaction (response). Endocrine System Works by means of chemicals (hormones) released into the bloodstream. The blood carries them all over the body. This system reacts slowly and produces effects that can last for hours, days and weeks. Homeostasis ❖ A system of glands and tissues that produce hormones in the body. ❖ A hormone is a chemical that circulates in the blood and plays a role in regulating almost all of your organs and tissues. Endocrine System Berthold’s Chickens GLANDS 2 Types of glands ❖ Exocrine glands secrete hormones through tubes or ducts. o ex. sweat, saliva, mucus Exocrine Glands ❖ Endocrine glands secrete hormones directly into the blood ❖ All endocrine cells are located in vascular areas (lots of blood vessels) to ensure that their products enter the blood immediately. Endocrine Glands  A chemical substance released by a cell or gland. Carries messages that affect cells/organs in other parts of the body. Each type of hormone is only recognized by specific tissues called target tissues. Hormones  Factors that affect hormone production and function 1. The amount of hormone released. 2. Hormone concentrations in the blood. 3. Blood flow in the target organ or tissue. 4. The half-life of the hormone (how long does it work in the body) minutes, hours, days… 5. Health problems (infection, injury, autoimmune disease.) Hormones  Hormones can stimulate the target tissue and increase its activity or inhibit the target tissue and decrease its activity. Hormones can cause a reaction in the cell to start, speed up, slow down or stop. Antagonistic action: certain hormones work against each other (from one extreme to the other) to return the body to its acceptable limits (homeostasis). ○ Ex: Blood sugar levels. Hormone Actions The two main types of hormones are: steroid and non-steroid. Steroid hormones are made up of cholesterol fat-soluble: this allows them to cross a cell membrane Non-steroid (protein) hormones are composed of proteins and amino acids. not fat-soluble (they cannot cross the membrane): they require receptors Types of hormones Complete the diagram of the glands as well as the table of hormones... ❖ An important link between the nervous system and endocrine system. ❖ Controls the secretion of hormones from the pituitary gland ❖ Produces releasing hormones: stimulates the production of other hormones 1. Hypothalamus gland ❖ The division between the nervous and endocrine system is in the hypothalamus. o The hypothalamus regulates (controls) the pituitary gland (hypophysis) with nerve stimulation and hormones. o The pituitary gland regulates the endocrine glands with chemical secretions which can also affect nerve activity in the hypothalamus. Link between systems ❖ This is the "master gland" which controls the other endocrine glands associated with hormones. ❖ Pituitary hormones are called stimulating hormones because pituitary hormones regulate the production of many other endocrine glands in the body. 2. Pituitary gland (hypophysis) ❖ Anterior lobe: controlled by the hypothalamus, produced by the pituitary o TSH: thyroid stimulating hormone, regulates cell metabolism o FSH: follicle stimulating hormone, stimulates the development of sperm and ovum. o LH: luteinizing hormone, stimulates ovulation and testosterone production o GH: « growth hormone » (somatotropin STH), stimulates growth o ACTH: adrenocorticotropic hormone, stimulates the secretion of hormones responsible for the stress response. o PRL: prolactin, stimulates milk production in females. ❖ Posterior lobe: stores and releases hormones from the hypothalamus o oxytocin: stimulates the contraction of the muscles of the uterus, triggers the release of milk. o ADH: antidiuretic hormone (increases water reabsorption) 2. Pituitary gland (hypophysis) ❖ Influences the cellular metabolic rate. ❖ Thyroxine: regulates heart rate, digestive organs, brain development, muscle control... ❖ Calcitonin: regulates levels of calcium in the blood. 3. Thyroid gland ❖ Located in the thyroid gland in the neck ❖ Controls the level of blood calcium 4. Parathyroid gland ❖ Located above the kidneys. ❖ Divide into 2 sections: ❖ Adrenal cortex: the outside of the gland ❖ Adrenal medulla: the interior Hormones produced by the Adrenal Medulla are adrenalin and noradrenalin. 5. Adrenal gland ❖ Production of hormones that regulate the level of sugar in the blood (glycaemia). o If the glycemic level is high, it secretes insulin to reduce the sugar level by forcing its storage in the liver, in fatty tissue and also in proteins in muscle tissue. o If the glycemic level is low, glucagon is produced and this forces the liberation of glucose from the storage areas. 6. Pancreas  Body cells take up more glucose Pancreas stimulated to release insulin into the blood Liver takes up Blood glucose level glucose and stores declines to a set point; it as glycogen (fat) stimulus for insulin release diminishes Stimulus: Rising blood blood glucose level Glucose level (e.g., after eating a carbohydrate-rich meal) Stimulus: Declining Homeostasis: Normal blood glucose level blood glucose level (e.g., after skipping a Glucose level meal) Blood glucose level rises to set point; stimulus for glucagon Pancreas stimulated to release diminishes release glucagon into the blood Liver breaks down glycogen and Glucagon releases glucose to the blood ❖ production of male sex hormone (testosterone) ❖ causes secondary sexual characteristics, stimulates sperm production. 7. Testicles ❖ Production of female sex hormones o estrogen: development of secondary sexual characteristics, prepares the uterus for pregnancy. o progesterone: maintains the uterus during pregnancy. 8. Ovaries ❖ Affects sexual development and biorhythms: Drowsiness (sleep) Mood disorders such as depression. Seasonal affective disorder. ❖ Hormone produced: melatonin Pineal gland (the epiphysis) ❖ Part of the immune system, the organ in which lymphocytes (T cells) mature ❖ Disappears after puberty. The spleen continues to produce T cells. ❖ Hormone produced: thymosin Thymus gland