SEHS Test 16/5/25 Flashcards
(24 cards)
What is the location and function of the hypothalamus?
The hypothalamus is a small but crucial region of the brain located below the thalamus and just above the brainstem.
The hypothalamus is a key regulator of homeostasis, it helps maintain the body’s internal balance.
- The hypothalamus acts as a bridge between the nervous and endocrine systems by communicating with the pituitary gland. It sends signals (either electrical or hormonal) that tell the pituitary which hormones to release into the bloodstream.
- The hypothalamus controls the pituitary gland, which then releases hormones like growth hormone (GH) and thyroid-stimulating hormone (TSH). These hormones regulate many body functions, such as growth, metabolism, and stress responses.
- The hypothalamus detects changes in body temperature and activates mechanisms like sweating or shivering to maintain balance. It also monitors nutrient and water levels, triggering hunger or thirst when needed. Additionally, it helps regulate the sleep-wake cycle by responding to light cues and managing melatonin release.
- The hypothalamus plays a role in emotional behavior by affecting areas of the brain involved in stress, fear, and aggression. It also influences the autonomic nervous system, which controls involuntary actions like heart rate and blood pressure, especially during stress or physical activity.
What is the location and function of thyroid gland
The thyroid gland is located in the front of the neck, just below the voice box. It wraps around the trachea and has a shape similar to a butterfly, with two lobes (left and right) connected by a thin strip of tissue
The thyroid gland is part of the endocrine system and plays a key role in regulating the body’s metabolism through the release of hormones. Its main functions include:
Producing thyroid hormones:
Thyroxine (T₄) and Triiodothyronine (T₃) regulate the rate of metabolism and how the body uses energy. These hormones affect almost every cell in the body, influencing heart rate, body temperature, and growth and development. Regulating calcium levels (indirectly):
The thyroid also produces calcitonin, a hormone that helps regulate blood calcium levels by reducing calcium in the blood and promoting storage in bones.
What is the location and function of the adrenal?
The adrenal glands are two small, triangular-shaped glands located on top of each kidney. They are part of the endocrine system and have two main parts, each with different functions:
- Adrenal Cortex (outer part):
Produces steroid hormones, including:
Cortisol – helps control metabolism, reduce inflammation, and manage stress.
Regulates blood pressure by controlling salt and water balance.
Androgens – small amounts of sex hormones that support development. - Adrenal Medulla (inner part):
Produces adrenaline (epinephrine) and norepinephrine:
These hormones prepare the body for “fight or flight” by increasing heart rate, blood pressure, and energy supply during stress.
What is the location and function of the parathyroid?
The parathyroid glands are four small glands (sometimes more) located behind the thyroid gland, in the neck. They are separate from the thyroid and have different functions.
Their main role is to regulate the body’s calcium levels by producing a hormone called parathyroid hormone (PTH). PTH helps:
Increase calcium levels in the blood by:
Releasing calcium from bones
Increasing calcium absorption from food (via vitamin D activation)
Reducing calcium loss in urine
Maintain phosphate balance in the blood
What is the location and function of the pancreas
The pancreas is located in the upper abdomen, behind the stomach. It lies horizontally across the body.
The pancreas has both endocrine and exocrine functions:
- Endocrine function (hormone production):
The pancreas contains clusters of cells which release important hormones into the bloodstream:
Insulin – lowers blood glucose levels by helping cells absorb glucose.
Glucagon – raises blood glucose levels by triggering the release of stored glucose from the liver.
These hormones help maintain blood sugar homeostasis. - Exocrine function (digestive enzyme production):
The pancreas produces digestive enzymes that are released into the small intestine to help break down carbohydrates, proteins, and fats.
What is the location and function of the pituitary gland?
The pituitary gland is a small, pea-sized gland located at the base of the brain. It sits just below the hypothalamus.
The pituitary is often called the “master gland” because it regulates many other endocrine glands in the body. It has two main parts with distinct functions:
- Anterior Pituitary (Front Lobe):
Produces and secretes several important hormones, including:
Growth hormone (GH) – regulates growth and development.
Thyroid-stimulating hormone (TSH) – stimulates the thyroid gland to produce thyroid hormones. - Posterior Pituitary (Back Lobe):
Stores and releases hormones produced by the hypothalamus:
Antidiuretic hormone (ADH) – helps regulate water balance by promoting water retention in the kidneys.
Oxytocin – stimulates uterine contractions during labor and helps with milk ejection during breastfeeding.
What is the location and function of the pineal gland?
The pineal gland is a small, pea-sized endocrine gland located in the center of the brain, in a groove where the two halves of the thalamus meet. It is situated just above the brainstem and behind the third ventricle of the brain.
The primary function of the pineal gland is the production and regulation of melatonin, a hormone that plays a key role in regulating sleep-wake cycles (circadian rhythms).
Key Functions:
Regulating sleep-wake cycles:
The pineal gland produces melatonin in response to darkness, which helps induce sleep and maintain the circadian rhythm. Light exposure inhibits melatonin production, signaling the body to wake up.
Influencing seasonal rhythms:
Melatonin production also helps regulate the body’s response to changes in light and dark cycles, affecting processes like seasonal reproduction in some animals.
What is the location and function of the ovaries?
Location: The ovaries are a pair of small, oval-shaped organs located in the pelvic cavity, on either side of the uterus. They are part of the female reproductive system.
Function:
Production of eggs (ova): The ovaries produce eggs (ova) for reproduction.
Hormone production:
Estrogen – responsible for the development of female secondary sexual characteristics (e.g., breast development, menstrual cycle regulation).
Progesterone – helps maintain pregnancy and prepares the uterus for implantation of a fertilized egg.
The ovaries also secrete small amounts of testosterone, although in much lower amounts than in males.
What is the location and function of the testes?
The testes are a pair of male reproductive organs located in the scrotum, a pouch of skin that hangs outside the male body, below the penis. This location helps maintain the optimal temperature for sperm production.
Function:
Sperm production: The testes produce sperm for reproduction.
Hormone production:
Testosterone – responsible for the development of male secondary sexual characteristics (e.g., facial hair, deep voice, muscle mass).
What is the function of the thymus?
The thymus is a soft, triangular-shaped gland located in the upper chest, behind the sternum (breastbone) and between the lungs. It is situated just above the heart and typically grows larger during childhood and then shrinks after puberty.
Function of the thymus:
The thymus plays a critical role in the immune system, particularly during childhood and adolescence.
Development of T-cells (T lymphocytes):
The thymus is essential for the maturation of T-cells, a type of white blood cell that is crucial for adaptive immunity. T-cells help the body fight infections by targeting and destroying infected cells.
Immune system education:
In the thymus, immature T-cells from the bone marrow undergo a process of selection, where they are “educated” to recognize the body’s own cells and distinguish them from foreign invaders. This process prevents the immune system from attacking the body’s own tissues (autoimmunity).
Secretion of hormones:
The thymus also produces several hormones, such as thymosin, which help in the development and maturation of T-cells.
What is the difference between hormones and neurotransmitters?
Hormones are chemical messengers produced by endocrine glands and released into the bloodstream, where they travel to distant target organs to regulate various physiological functions, such as metabolism, growth, and mood. They have a slower onset and longer duration of action compared to neurotransmitters.
On the other hand, neurotransmitters are chemicals released by neurons (nerve cells) at synapses to transmit signals across nerve cells. They act quickly and typically have a short duration of action, influencing immediate responses such as muscle contraction, heart rate, or mood regulation. While hormones act throughout the body, neurotransmitters primarily function within the nervous system.
Insulin and why and when is it released
Insulin is a hormone produced by the pancreas, specifically by the beta cells. It is released in response to elevated blood glucose levels, typically after eating a meal that contains carbohydrates. Insulin helps lower blood sugar by facilitating the uptake of glucose into cells for energy or storage as glycogen in the liver and muscles. It is released to maintain blood glucose homeostasis, ensuring that blood sugar levels remain within a healthy range. The release of insulin is particularly important in managing the body’s energy balance and preventing high blood sugar.
What is the function and purpose of adrenaline/ephineprine.
Adrenaline (epinephrine) is a hormone and neurotransmitter produced by the adrenal glands in response to stress or danger, triggering the fight-or-flight response. It increases heart rate, blood pressure, and blood flow to muscles, preparing the body for quick action. Additionally, adrenaline dilates t he airways to improve oxygen intake and releases stored energy (glucose) for immediate use. Its overall purpose is to help the body respond to acute stressors by enhancing physical performance, focus, and alertness during emergencies or perceived threats.
Explain the role of glucose
Glucose is a simple sugar and a primary source of energy for the body’s cells. It is absorbed into the bloodstream after the digestion of carbohydrates and is transported to cells, where it is used in cellular respiration to produce ATP (adenosine triphosphate), the energy currency of the cell. Glucose levels in the blood are tightly regulated to ensure that cells receive a constant supply of energy, especially the brain, which relies heavily on glucose. When blood glucose levels are too high, insulin helps store excess glucose as glycogen in the liver and muscles, while low blood glucose triggers the release of glucagon to release stored glucose.
What is the interaction between the nervous system and endocrine system?
The nervous system and endocrine system interact closely to maintain homeostasis and regulate bodily functions. The hypothalamus, a part of the brain, acts as a link between the two systems, receiving signals from the nervous system and releasing hormones that influence the pituitary gland, which controls other endocrine glands. For example, in response to stress, the nervous system triggers the release of adrenaline from the adrenal glands, while the hypothalamus signals the release of cortisol through the pituitary. This collaboration allows for both immediate responses (through the nervous system) and longer-term regulation (through the endocrine system) in processes like metabolism, growth, and stress management.
Explain the purpose and function of hormone-receptor specificity
Hormone-receptor specificity ensures that hormones only affect certain target cells, which have the appropriate receptors to bind the hormone. This specificity allows hormones to produce precise effects on specific tissues or organs, preventing widespread, non-targeted actions. The binding of a hormone to its receptor triggers a series of intracellular signals that initiate the desired biological response, such as changes in gene expression, metabolism, or growth. Without this specificity, hormones could affect any cell, leading to potentially harmful or uncoordinated responses. In essence, it ensures that each hormone’s effects are targeted and regulated for proper physiological functioning.
Explain the purpose and function of temperature regulation
Temperature regulation is crucial for maintaining the body’s internal environment within a narrow range that supports optimal enzyme activity and overall metabolic function. The body uses mechanisms like sweating, shivering, and changes in blood flow to adjust to temperature fluctuations. When the body gets too hot, it releases heat through sweating and by dilating blood vessels near the skin (vasodilation). When it gets too cold, the body conserves heat by shivering and constricting blood vessels near the skin (vasoconstriction). This regulation ensures that the body maintains a stable internal temperature, typically around 37°C (98.6°F), which is essential for normal physiological processes and overall health.
Training in hot and cold weather (what should you do/what will your body do to maintain homeostasis)?
Training in hot weather causes the body to work harder to maintain a stable internal temperature. To prevent overheating, the body activates mechanisms like sweating to cool down and vasodilation to increase blood flow to the skin, allowing heat to dissipate. However, it’s important to stay hydrated and take breaks to avoid heat exhaustion or heat stroke. In cold weather, the body tries to conserve heat by triggering shivering to generate warmth and vasoconstriction to reduce heat loss from the skin. Wearing appropriate clothing and layering can help prevent hypothermia by supporting the body’s efforts to maintain heat balance during cold training conditions.
Explain the purpose and function of cold stress
Cold stress refers to the physiological response the body has when exposed to cold temperatures, which challenges its ability to maintain homeostasis and normal internal temperature. The body activates several mechanisms to combat cold stress and prevent heat loss, including shivering (which generates heat through muscle activity) and vasoconstriction (narrowing of blood vessels near the skin to conserve heat). Cold stress can lead to increased energy expenditure as the body works harder to regulate its temperature. Prolonged cold exposure without proper protection can result in hypothermia, where the body’s temperature drops to dangerously low levels.
Homeostatic control mechanisms and feedback loops in regulation of blood PH
The body regulates blood pH to maintain a stable internal environment, using homeostatic control mechanisms and feedback loops. When blood pH becomes too acidic (low) or too alkaline (high), the body uses buffer systems (like bicarbonate) to neutralize excess acids or bases. The respiratory system helps by adjusting breathing rate to remove carbon dioxide (which lowers pH), while the renal system (kidneys) excretes or retains acids and bicarbonates to restore balance. These feedback loops ensure the blood pH remains within the narrow range of about 7.35 to 7.45, which is necessary for proper cellular function.
Homeostatic control mechanisms and feedback loops in regulation of the heart (intrinsic and extrinsic excitation)
The regulation of the heart’s activity involves both intrinsic and extrinsic mechanisms to maintain homeostasis. Intrinsic regulation refers to the heart’s natural ability to control its rhythm through the sinoatrial (SA) node, which acts as the heart’s pacemaker and generates electrical impulses to trigger heartbeats. Extrinsic regulation involves external control from the autonomic nervous system (sympathetic and parasympathetic), which adjusts the heart rate in response to changes in the body’s needs (e.g., increasing heart rate during exercise). These mechanisms work together in a feedback loop to ensure the heart maintains an appropriate rate and force of contraction to meet the body’s demands.
Homeostatic control mechanisms and feedback loops in regulation of Blood Glucose
The regulation of blood glucose levels is controlled by homeostatic feedback loops to keep the body’s glucose level within a narrow range. When blood glucose rises after eating, the pancreas releases insulin, which helps cells absorb glucose and store excess as glycogen, lowering blood glucose. If blood glucose falls too low, the pancreas releases glucagon, which signals the liver to release stored glucose back into the bloodstream. These feedback mechanisms help maintain blood glucose at a stable level, ensuring the body has a steady energy supply.
Homeostatic control mechanisms and feedback loops in regulation of body temperature
The body regulates temperature through homeostatic control mechanisms using feedback loops to keep it within a safe range (around 37°C or 98.6°F). When the body gets too hot, it activates sweating to cool down and vasodilation to increase blood flow to the skin, releasing heat. When it’s too cold, the body uses shivering to generate heat and vasoconstriction to reduce heat loss by narrowing blood vessels near the skin. These responses help the body maintain a stable internal temperature for proper functioning.
Stimuli and receptors including Reflex arc
Stimuli are changes in the environment that trigger a response, and receptors are specialized cells or organs that detect these stimuli, such as light, heat, or pressure. Once a receptor detects a stimulus, it sends an electrical signal through sensory neurons to the central nervous system. The reflex arc is a quick, involuntary pathway that allows the body to respond to stimuli without needing to think about it, such as pulling your hand away from something hot. This system helps protect the body by enabling fast reactions to potentially harmful stimuli.
