4003 A+P Revision PDF

**[4003 A+P revision]** 1. **[Where is the sperm produced?]** - The process of sperm development (spermatogenesis) takes place inside the testes 2. **[What hormones are responsible for secondary sexual characteristics?]** - **Testosterone (Testes in males)** (deeper voice, facial b...

**[4003 A+P revision]** 1. **[Where is the sperm produced?]** - The process of sperm development (spermatogenesis) takes place inside the testes 2. **[What hormones are responsible for secondary sexual characteristics?]** - **Testosterone (Testes in males)** (deeper voice, facial body hair and growth, increased bone density, broader shoulders) - **Estrogen (Ovaries in females)** (Breast development, widening of hips, menstrual cycle regulation, fat distribution in hips, thighs, buttocks) - **Progesterone (Ovaries in females)** (Progesterone works alongside estrogen to regulate the menstrual cycle and pregnancy, plays role in breast development and preparation of uterus for pregnancy) - **Growth hormone (GH) (produced in pituitary gland)** (Promotes overall growth and stimulates growth and development of bones, muscles and other tissues) - **Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) (Ovaries in females/testes in males)** (LH stimulates the production of testosterone in males and Strogen in females and FSH supports sperm production in males and egg maturation in males) - **Dihydrotestosterone (DHT) (Males)** (This hormone stimulates the development of male characteristics, responsible for growth of face and body hair, contributes to development of the prostate and other male reproductive structures, and affects the deepening of voice and other male features) - **Androgens (general term for male sex hormones)** (Group of hormones that include testosterone and DHT. Testosterone androgens contribute to muscle development, body hair growth and voice deepening in males) **Summary of Key Characteristics and hormones:** **Males:** Testosterone, DHT and growth hormone are responsible for facial hair, body hair, muscle mass, deepened voice, and changes in reproductive organs. **Females:** Estrogen and progesterone drive the development of breasts, widening hips, fat distribution, and the maturation of the reproductive system. 3. **[What is the function of the fallopian tubes?]** - The fallopian tubes are also known as the uterine tubes or oviducts and they main function is to transport eggs from the ovaries to the uterus and provide the site for fertilisation. - After the release of an egg from the ovary (ovulation), the egg enters the fallopian tubes through a structure called the fimbriae which are finger like projections at the end of the tube to help capture the egg. Once inside the tube cilia (little hairs) help move the egg towards the uterus. - The fallopian tubes provide a nutrient-rich environment to support the egg and early stages of the embryo (if fertilisation occurs) The tube secretes substances that nourish the egg and support the passage to the uterus. 4. **[What is the function of the oesophagus?]** - The oesophagus is a muscular tube that connects the throat (pharynx) to the stomach. The main functions of this are transporting food, liquids and saliva from the mouth to the stomach. - The process of swallowing involves lots of muscle contractions, the muscles contract and relax, pushing the food down towards the stomach. - There is mucus on the oesophagus lining as this helps food move down and protects from any damage and from the acidic environment in the stomach. 5. **[What is the position of the oesophagus and what structures does it pass through?]** - The oesophagus starts just behind your windpipe (trachea) and runs down your neck. It\'s also behind the voice box (larynx) and the area where your throat connects to your mouth (pharynx). **[Structures it passes through:]** **[Summary of the oesophagus:]** - The oesophagus starts in the neck, travels down through the chest, passes through the diaphragm and connects to the stomach. - It passes through important structures like the trachea, heart and aorta. - There are two key muscles that help control food movement which are the upper oesophageal sphincter and the lower. 6. **[What does the stomach do, how does it help with digestion and what acid is involved?]** - The stomach is the key organ in the digestive system and its role is to break down food both chemically and, mechanically so that the body can absorb nutrients **[How the stomach helps with digestion?]** - **Holds and mixes food:** When food is swallowed this goes down through the oesophagus into the stomach. The stomach acts as a storage area where food is held for several hours. It mixes food with digestive juices to help break the food into smaller, more digestible pieces. (Chyme) - **Breaks down food mechanically:** The stomach has strong muscles that churn and mix up the food with digestive enzymes and acid that chemically break down food. This is important for digesting proteins, which are harder to break down than carbohydrates and fats. - **Breaks food down chemically:** The stomach secretes gastric juices that contain enzymes and acid that chemically break down food. These juices are acids and enzymes, and they help break down other nutrients in the food **[Acid that is involved?]** - Hydrochloric acid (HCI) helps digest food - Hydrochloric acid **helps us digest protein** as it activates an enzyme called **pepsin,** which breaks down food into smaller pieces - This acid kills germs and any harmful bacteria in the food keeping you safe - The acid makes the stomach very acidic, which is needed to digestion (PH of 1.5 to 3.5) **[Summary of the stomach:]** - The stomach helps break down food by mixing and churning it and by using acids and enzymes - Hydrochloric acid is the main acid that helps digest food and kill germs - The stomach also has pepsin, an enzyme that break down proteins - The stomach is protected by mucus, so acid doesn't damage it - This process prepares food for the small intestine, where nutrients will get absorbed into the bloodstream 7. **[How does the small bowel movement contribute to absorption- think about surface area?]** - In the small intestine, surface area is the key to absorbing nutrients well. The more surface area, the more nutrients the small intestine can absorb. **Villi**: The inner surface of the small intestine has tiny, finger-like projections called **villi**. These increase the surface area available for absorption. Each villus (singular form of villi) is lined with even smaller projections called **microvilli**, which further increase the surface area. Think of it like a sponge---if it has a lot of tiny holes (villi and microvilli), it can soak up more liquid (nutrients in this case). **Microvilli**: On the surface of each villus, there are **microvilli** (even smaller finger-like structures), which look like a "brush border." These microvilli contain enzymes that help break down food even further (e.g., carbohydrates and proteins) into small molecules that can be absorbed into the blood. **Length of the Small Intestine**: The small intestine is about 6 meters long (about 20 feet), and it's coiled up inside the abdomen, which also increases the surface area. This long, coiled structure gives the digestive enzymes and absorbed nutrients plenty of time to work. **[How surface area helps absorption?]** - **More area = More absorption:** The increased surface area (from villi and microvilli) allows for a larger amount of nutrients to be absorbed at once. This includes sugars, amino acids (from proteins), fats, vitamins, and minerals. - **Efficient nutrient absorption:** Efficient nutrient absorption: As food is broken down into smaller molecules (like glucose, amino acids, and fatty acids), these molecules are absorbed through the walls of the villi and enter the bloodstream or lymphatic system, where they're transported to the rest of the body. **[Summary of the surface area and absorption:]** - The villi and microvilli in the small intestine create a large surface area for absorption, allowing nutrients from food to be absorbed efficiently - The length and coiling of the small intestine also contribute to more time for digestion and absorption to occur. - All of this helps ensure the body gets the nutrients in it from the food you eat - the design of the small intestine is all about maximizing **surface area** to improve nutrient absorption. The more surface area, the more efficient the absorption of nutrients like carbohydrates, proteins, and fats 8. **[What are the components of the blood? - what makes up our blood?]** 1. **Plasma: [ ]**The liquid part of blood that carries nutrients, waste, hormones and gases (acts as the carrier for carrying the nutrients, waste products, hormones and gases round the body) 2. **Red blood cells: [ ]**carry oxygen and carbon dioxide throughout the body (RBCs contain a protein called **haemoglobin**, which binds to oxygen in the lungs and releases it in tissues that need it. Haemoglobin also helps transport carbon dioxide back to the lungs) 3. **White blood cells:** fight infections and protect the body from illness (help fight infections and protect the body from disease. They are your body's defence system) 4. **Platelets:** Help with blood clotting to prevent bleeding. Also help with the healing of wounds. Platelets have some immune functions and can interact with white blood cells to support inflammatory responses, such as fighting infections. Overall platelets are essential for stopping bleeding by forming a clot and helping tissue repair. Their ability to stick to damaged blood **[How the components of blood work together:]** 1. **Oxygen transport and delivery-** Red blood cells pick up oxygen in the lungs and deliver it to tissues in the body. Plasma helps transport nutrients and gases such as oxygen and carbon dioxide around the body, It also carries waste products to the kidneys for excretion. 2. **Immune Response:** White blood cells patrol the body for pathogens. If an infection is detected white blood cells respond by engulfing the pathogens or producing antibodies. Plasma helps transport immune system components like antibodies and other signalling molecules to stop an infection. 3. **Blood clotting:** When blood vessels are damaged, platelets quickly form a plug, while clotting factors (protein in the plasma) help create a fibrin mesh to stop bleeding. This process helps prevent any excessive blood loss. 4. **Regulation of fluid balance:** Plasma proteins like albumin help maintain the osmotic balance between blood and tissues, preventing fluid from leaking out of the blood vessels into the tissues, which could lead to swelling (edema). - Plasma is the liquid portion of the blood, which contains water, proteins, electrolytes, nutrients, hormones and waste products - Cells such as red and white blood cells and platelets - Together, each of these components work together to transport gases, nutrients, hormones, and waste, support immune responses and help maintain fluid and electrolyte balance 9. **[What is the structure of the heart and the name of the valves, and where are they and what do they do? (Preventing backflow into the... part of the heart)]** Understanding Heart Valve Disease \| Knight Cardiovascular \... - The heart is a muscular organ that pumps blood around the body, however it is divided into four chambers which are: - **Two atria (upper chambers) and two ventricles (lower chambers)** - To ensure that blood follows in one direction and prevents blood flow, the heart has **four valves** that act as gates between the chambers and blood vessels **[Structure of the heart]** **[Right atrium:]** Receives deoxygenated blood from the body (via the superior and inferior vena cavae) **[Left atrium:]** Receives oxygenated blood from the lungs (via the pulmonary veins) **[Right ventricle:]** Pumps deoxygenated blood to the lungs (via the pulmonary artery) **[Left ventricle:]** Pumps oxygenated blood to the rest of the body (via the aorta) **[The heart valves]** - The heart has valves which ensure that blood flows in only one direction, which prevents any backwards flow (regurgitation). There are four valves in the heart: 1. **[Tricuspid Valve:]** 2. **[Pulmonary Valve:]** 3. **[Bicuspid (mitral) Valve]** 4. **[Aortic Valve]** - In the heart, each valve has flaps, called **cusps** that open and close with the heartbeat to control blood flow. - When the heart pumps, the pressure forces the valve to open and allow blood to flow in the right direction. After the blood passes through, the pressure drops, causing the valve to close, preventing any blood flowing backwards. - This is important to keep blood moving in the body in one direction, ensuring that oxygenated blood reaches the body and deoxygenated blood flows to the lungs - When the heart contracts, the valves open to let blood through - As the heart relaxes, the valves close tightly to stop blood flowing backwards **[Summary of the heart Valves:]** - Valve are located between the heart chambers and blood vessels - Their job is to **prevent backflow of blood** making sure that only it flows in one direction - Without valves, blood would flow backward, making the heart less efficient in circulating blood to the body and lungs - Valve function is a critical part for the heart to work properly and maintain a healthy circulatory system **[What is the correct blood flow passage through the heart?]** - The path blood takes through the heart follows a specific sequence to ensure that it is properly oxygenated and pumped to the body and lungs: 1. **Deoxygenated Blood** from the body enters the heart- (Superior and inferior vena cava (large veins) bring deoxygenated blood from the body into the right atrium) 2. **Right atrium:** (The right atrium receives the deoxygenated blood and contracts to push it through the tricuspid valve into the right ventricle) 3. **Right ventricle:** (The right ventricle contracts, pumping the deoxygenated blood through the pulmonary valve into the pulmonary artery) 4. **Pulmonary artery:** (The pulmonary artery carries the blood to the lungs, where it gets oxygenated, exchanging carbon dioxide for oxygen) 5. **Oxygenated blood** returns to the heart- (After oxygenation in the lungs, the pulmonary veins carry the oxygen-rich blood back to the left atrium of the heart) 6. **Left atrium:** (The left atrium receives the oxygenated blood and contracts to push it through the bicuspid "mitral" valve into the left ventricle) 7. **Left ventricle:** (The left ventricle, the most muscular chamber, contracts and pumps the oxygenated blood through the aortic valve into the aorta) 8. **Aorta:** (The aorta, which is the bodys largest artery, carries the oxygenated blood throughout the body to deliver oxygen and nutrients to tissues and organs) **[Summary of Blood Flow Path:]** 1. **Body **(deoxygenated blood) → **Superior/Inferior Vena Cava** → **Right Atrium** 2. **Right Atrium** → **Tricuspid Valve** → **Right Ventricle** 3. **Right Ventricle** → **Pulmonary Valve** → **Pulmonary Artery** → **Lungs** (oxygenation) 4. **Lungs **(oxygenated blood) → **Pulmonary Veins** → **Left Atrium** 5. **Left Atrium **→ **Bicuspid (Mitral) Valve** → **Left Ventricle** 6. **Left Ventricle** → **Aortic Valve** → **Aorta** → **Body** (oxygenated blood) - This continual cycle ensures that blood is properly oxygenated in the lungs and then circulated to the rest of the body for metabolic functions, while deoxygenated blood is sent to the lungs for oxygenation 10\. **[What are the names of the white blood cells?]** 1. **Neutrophils** -- Fight bacterial infections. 2. **Lymphocytes** -- B-cells (produce antibodies), T-cells (kill infected cells). 3. **Monocytes** -- Become macrophages (phagocytosis, clean up dead cells). 4. **Eosinophils** -- Defend against parasites, involved in allergic reactions. 5. **Basophils** -- Release histamine and heparin during allergic reactions and inflammation. - To help remember with this think of **"Never Let Monkeys Eat Bananas"**. This helps remember the order **[11. In the kidneys what is filtered and what isn't and what normally passes through the glomerular filtration membrane and what doesn't?]** - **The glomerular filtration membrane** is like a filter in the kidney's glomerulus (a network of tiny blood vessels). It allows some substances to pass through and stay in the **filtrate** (the fluid that will eventually become urine), **whilst keeping others in the blood**) **[What normally passes through the Glomerular filtration Membrane and what is filtered?]** - Small substances pass easily through the glomerular membrane, and they are filtered from the blood into the **Bowman's capsule** this includes: **[What is not filtered?]** - **The glomerular membrane** is very selective meaning that it does not allow larger molecules or important components to pass through. These are **kept in the blood** and not filtered into the urine: - The glomerular filtration membrane is like a mesh that only lets small particles and water pass through. **Larger particles** like **blood cells** and **large proteins** are **too big** to get through and stay in the bloodstream. **[Visualising this filtration process]** **Filtered (Pass through) =** Small substances like water, electrolytes, waste products, and small molecules e.g glucose, urea, creatinine **Not filtered (stays in the blood) =** Blood cells red blood cells, white blood cells and platelets and large proteins such as albumin and globulins **[Why this process is important?]** - The kidneys main job is to filter out any waste products and excess substances from the blood, whilst keeping things such as blood cells and proteins that the body needs to stay healthy - The filtered fluid then moves through the **nephrons**, where the body decides what to keep e.g water and nutrients and what to get rid of and excrete such as urine **[Summary]** - **What passes through:** small substances like water, electrolytes, waste products, and small molecules (e.g glucose, urea and creatinine) - **What doesn't pass through:** Blood cells, platelets and large proteins - This filtration process is essential for removing waste from the blood and maintaining balance in the bodys fluids and electrolytes **[12. What waste products are excreted by the kidneys- know what nitrogenous means?]** - The kidneys play a key role in removing waste products from the blood that the body no longer needs. These waste products are mostly produced from metabolism (the breakdown of food and other substances in the body) Here are the main waste products excreted by the kidneys: **1. [Urea:]** **What it is:** Creatinine is a waste product of muscle metabolism. It comes from the breakdown of a compound called creatine in muscles, which provides energy for muscle contractions. **How is it excreted:** Urea travels through the bloodstream to the kidneys, where it is filtered out and excreted in the urine. **2. [Creatinine:]** **What it is:** Creatinine is a waste product of muscle metabolism. It comes from the breakdown of a compound called creatine in muscles, which provides energy for muscle contractions. **How it's excreted:** Like urea, creatinine is filtered out by the kidneys and excreted in the urine. It's often used to assess kidney function because its levels in the blood remain relatively constant. **3. [Uric Acid:]** **What it is:** Uric acid is produced from the breakdown of purines, which are found in certain foods and in the DNA of cells. **How it's excreted:** Uric acid is filtered out by the kidneys and excreted in the urine. If the kidneys don\'t excrete enough uric acid, it can lead to gout, a condition where uric acid crystals form in joints. **[13. What is the difference between the sympathetic and parasympathetic nervous system, and which one would be stimulated when in danger?]** - The sympathetic and parasympathetic nervous systems are two branches of the autonomic nervous system (ANS), which controls involuntary body functions such as heart rate, digestion, and respiration. These two systems have opposing effects and are responsible for regulating the body\'s responses to various situations. Here\'s a breakdown of their differences: **[Sympathetic Nervous System (SNS)]** **Function:** The sympathetic nervous system is primarily responsible for preparing the body for \"fight or flight\" responses during stressful or dangerous situations. **Effects:** Increases heart rate, dilates pupils, increases blood flow to muscles for faster movement, increases blood sugar for energy, stimulates the release of adrenaline from the adrenal glands (epinephrine) **When it\'s activated**: The sympathetic nervous system is triggered in response to stress, danger, or emergency situations. It prepares the body for quick action and heightened alertness. **[Parasympathetic Nervous System (PNS)]** **Function**: The parasympathetic nervous system is responsible for maintaining the body's **\"rest and digest\"** state. It promotes relaxation, conservation of energy, and recovery after stress. **Effects:** Slower heart rate, constricts pupils, reduces blood flow to muscles because the body isn't in state of emergency, promotes energy storage and recovery, stimulates digestion and production of saliva. **When it\'s activated**: The parasympathetic nervous system is activated during restful or calm states, such as after eating or during relaxation. It helps the body return to a balanced, restful state after the activation of the sympathetic nervous system. **Which system is activated in danger?** - In **dangerous** or **stressful situations**, the **sympathetic nervous system (SNS)** is the one that gets activated. This leads to the **\"fight or flight\"** response, which prepares the body for immediate action---whether that's to fight or flee from a perceived threat. - So, when you\'re in danger, the sympathetic nervous system is the one that stimulates physiological changes like increased heart rate, rapid breathing, and heightened alertness to help you respond effectively to the threat. **14. Where does a nerve cell receive its messages, and what is the structure of a nerve cell?** - A nerve cell, also called a neuron, receives its messages (or signals) through a part of the cell called the dendrites.  **[Where does a nerve cell receive its messages?]** - **Dendrites**: These are the branch-like structures that extend from the cell body of the neuron. Dendrites receive electrical signals (messages) from other neurons or sensory receptors and send them toward the **cell body**. - **Dendrites**: These are the branch-like structures that extend from the cell body of the neuron. Dendrites receive electrical signals (messages) from other neurons or sensory receptors and send them toward the **cell body**. **[What is the structure of a nerve cell?]** **[A neuron has three main parts:]** 1. **Cell Body (Soma)**: The cell body contains the **nucleus** and most of the cell\'s organelles (like mitochondria, ribosomes). It's like the \"control center\" of the neuron, where most metabolic processes happen. 2. **Dendrites**: Short, branched extensions that receive **incoming messages** from other nerve cells or sensory receptors. These messages are in the form of **electrical impulses**. 3. **Axon**: A long, thin fiber that **sends electrical impulses** away from the cell body to other neurons, muscles, or glands. The axon can be very long (up to a meter in some cases) and is often covered by a fatty layer called **myelin**. **Myelin** helps speed up the transmission of electrical signals and insulates the axon. The gaps between myelin are called **nodes of Ranvier**, which help with faster signal transmission. 4. **Axon Terminals (Synaptic Terminals)**: The axon ends in tiny branches called axon terminals. These release chemicals called **neurotransmitters** that **carry the message** to the next neuron or target cell (like a muscle or gland). **[Summary]** - Messages are received by the dendrites. - The cell body processes the information. - The axons send the message to the next neuron or tissue. - This structure allows nerve cells to communicate quickly and effectively within the nervous system!