Response to Stimuli PART 2.pptx

Year 9 Response to Stimuli Part 2 Content Review Endocrine System Menstraul Cycle Media Analysis Assessment Monday Aug 9th Learning Objectives  The endocrine system consists of many glands that release hormones into the circulatory system which trigger responses...

Year 9 Response to Stimuli Part 2 Content Review Endocrine System Menstraul Cycle Media Analysis Assessment Monday Aug 9th Learning Objectives  The endocrine system consists of many glands that release hormones into the circulatory system which trigger responses in target cells  The stimulus response model (stimulus, receptor, modulator, effector, response) is involved in homeostasis and body function  The menstrual cycle is an example of endocrine control Endocrine System Communication Systems McRae,  Chemical Signals  Hormones Endocrine Glands release Chemical Signals (Hormones) into the bloodstream Although hormones are carried to all parts of your body, only particular cells have receptors for particular hormones. Like a key and lock system, only some cells have specific locks (receptors) that fit with a specific key (hormone) Hormone A represents a water-soluble Hormone B represents a lipid-soluble hormone, which stimulates receptor A hormone which can pass through the on the outer membrane of the target cell membrane and attach to receptor cell. B inside the target cell. Water-soluble hormones tend to be faster acting than lipid-soluble hormones, but their effects are usually shorter lived. Endocrine glands  Hypothalamus  Pituitary  Thyroid  Parathyroids  Adrenal glands  Pancreas  Ovary  Testes McRae, Booklet Practice Booklet Practice Negative Feedback Loop The endocrine system operates with feedback loops. 1. Like the nervous system, a stimulus is detected by a receptor. 2. This signal is passed onto a control centre (gland) that activates an effector (target cell) by releasing a hormone. 3. The target cell does what it is instructed to do by the hormone, causing the response. 4. The response eventually changes the cause of the stimulus. Example 1: Thermoregulation Example 2: Low Blood Glucose Levels Diabetics Menstrual Cycle  Understanding the Cycle The menstrual cycle is a natural process that happens in the female body. It's important because it prepares the body for pregnancy, even though not everyone might know a lot about it. What is the Menstrual Cycle? Definition: The menstrual cycle is a monthly series of changes that a woman's body goes through to get ready for a possible pregnancy. Length: It usually lasts about 21 to 35 days, but can vary from person to person. Female Reproductive System The three main parts we will focus on is the: Ovary/Ovaries – two small organs on either side of the Uterus Role: Produces eggs (ova) and female hormones (progesterone & estrogen) which regulates the menstrual cycle and supports pregnancy Fallopian Tubes – pair of tubes extending from Ovaries to Uterus Role: Transports egg from Ovary to Uterus and typically where fertilization of egg occurs by sperm Uterus: pear shaped hollow organ located in pelvis Role: Houses the fertilized egg as it develops to fetus Role: Houses and nourishes the fertilized egg as it develops into a fetus. It also has a lining (endometrium) that thickens and sheds during the menstrual cycle. The Cycle The cycle is divided into four phases: 1) Menstruation (Days 1-5) This is when bleeding occurs, which is called menstruation. It happens because the body is shedding the lining of the uterus (the endometrium) if there’s no pregnancy. Also commonly known as a Period. How it Feels: may have cramps, feel tired, or experience mood changes. 2) Follicular phase 3) Ovulation 4) Luteal phase. The Cycle The cycle is divided into several phases: 1) Menstruation (Days 1-5) 2) Follicular phase (Days 1-13) After menstruation, the body starts preparing a new egg for release. The ovaries produce hormones that make the uterine lining thick again. How it Feels: Many people feel energetic and healthy as their body is getting ready for the next phase. 3) Ovulation 4) Luteal phase. The Cycle The cycle is divided into several phases: 1) Menstruation (Days 1-5) 2) Follicular phase (Days 1-13) 3) Ovulation (Around Day 14) An egg is released from one of the ovaries and travels down the fallopian tube. This is the time when a woman is most likely to get pregnant. How it Feels: Some might feel a bit of pain or discomfort, but many don’t notice anything special. 4) Luteal phase. The Cycle The cycle is divided into several phases: 1) Menstruation (Days 1-5) 2) Follicular phase (Days 1-13) 3) Ovulation (Around Day 14) 4) Luteal phase (Days 15-28) The body prepares for a possible pregnancy. -> If the egg isn’t fertilized, the hormone levels drop, and the uterine lining starts to break down (leading to Menstruation again) How it Feels: Symptoms like mood swings, bloating, and fatigue can occur. This is sometimes referred to as PMS (pre-menstrual syndrome). Hormones that Drive the Menstrual Cycle The cycle is regulated by a complex interplay of four hormones: The pituitary gland in the brain releases Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). Follicle Stimulating Hormone (FSH) 1. Stimulates the growth of ovarian follicles, each containing an egg. 2. As the follicles grow, they produce estrogen/oestrogen which thickens the lining of the uterus to prepare for the embedding of a fertilised egg. The cycle is regulated by a complex interplay of four hormones: The pituitary gland in the brain releases Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). Luteinizing Hormone (LH) 3. Around the middle of the cycle (Day 14), a surge in LH triggers ovulation, the release of a mature egg from the dominant follicle. 4. This egg travels down the fallopian tube, where it may meet sperm and become fertilized. 5. After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. Progesterone further thickens the uterine lining, making it more  If fertilization does not occur  The corpus luteum breaks down, leading to a drop in progesterone and estrogen levels, which causes the uterine lining to shed = menstruation (new cycle begins) Throughout the cycle, the coordinated actions of the four hormones (FSH, LH, progesterone & estrogen) ensure the proper development of the egg, the preparation of the uterine lining, and the resetting of the cycle. Video on the Reproductive Regulation Video on the Menstrual Cycle  Media Analysis Below is a guide to analysing an article (from the booklet): 1. Read through the article carefully from start to end without making notes. 2. Work through the article a second time and identify terms that you do not fully understand. Highlight them, look them up and write a definition. 3. Identify the main ideas of the article and write them as dot points on another piece of paper. 4. Annotate the article to identify connections to the content you have learned in this module. The learning objectives can be found at the start of this booklet and on Canvas. 5. Write a short summary of the article by expanding your main ideas dot points into a few simple sentences of your own words.