bio paper 2

What is homeostasis?

The regulation of conditions inside the body to maintain a stable internal environment in response to internal and external conditions.

What components are involved in the body's automatic control systems for homeostasis?

Receptors, coordination centers (brain and spinal cord), and effectors (muscles or glands).

How does the nervous system communicate changes in the body?

By sending very fast and precise electrical impulses through nerves.

What is the role of the endocrine system in homeostasis?

It relies on hormones released into the bloodstream, affecting certain cells and providing slower, longer-lasting, and more generalized responses.

What is negative feedback in the context of homeostasis?

A process that decreases a level when it gets too high and increases it when too low, creating a loop that counteracts changes.

What is the structure and function of a neurone?

A nerve cell adapted to carry electrical impulses, characterized by being long, thin, and having branched connections.

What is a synapse?

The connection between nerve cells where an electrical impulse triggers the release of chemicals that diffuse across the gap to initiate another impulse.

What does the central nervous system consist of?

The brain and spinal cord.

How does the central nervous system receive and send information?

It receives information via sensory neurons and sends information back out via motor neurons to effectors.

What is the reflex arc?

A pathway that involves unconscious reflexes, where a stimulus is detected by receptor cells and an impulse is carried to the spinal cord, skipping the brain for a quicker response.

What are the main functions of the cerebral cortex?

Responsible for consciousness, intelligence, memory, language, and processing sensory information.

What is the role of the cerebellum?

Responsible for balance and muscle coordination.

What does the hypothalamus regulate?

Body temperature and signals to the pituitary gland.

What is the function of the medulla in the brain stem?

Controls unconscious activities such as breathing and heart rate.

How can scientists study the brain?

By studying brain damage, electrically stimulating parts of the brain, and using scanning techniques like CT, PET, and MRI scans.

What challenges are faced in treating brain conditions?

The complexity of brain functions, difficulty accessing it due to the skull, and the wide range of potential issues like tumors and infections.

What is the sclera?

The tough white layer that encases the eye and protects it from damage.

What is the cornea's role in the eye?

A transparent front part of the eye that refracts light.

What is the function of the pupil?

A hole in the middle of the eye that allows light to enter.

How does the iris function in the eye?

It adjusts the size of the pupil depending on light levels.

What is the function of the lens in the eye?

The lens adjusts its shape to focus on near and distant objects.

What are the two types of receptor cells in the retina and their functions?

Rod cells are sensitive to dim light, while cone cells allow us to see in color.

How does the pupil respond to bright light?

In bright light, the circular muscles contract to make the pupil smaller, while the radial muscles relax.

What happens to the pupil in low light conditions?

In low light, the circular muscles relax and the radial muscles contract, allowing the pupil to dilate.

What is accommodation in the context of vision?

Accommodation is the process by which the lens changes shape to focus on near or distant objects.

How do ciliary muscles affect the lens when focusing on distant objects?

Ciliary muscles relax, making the circle wider, which stretches the suspensory ligaments and flattens the lens.

What occurs when focusing on near objects?

Ciliary muscles contract, making the lens thicker and more curved to increase refraction.

What is short-sightedness (myopia)?

Short-sightedness is when people cannot focus on distant objects due to the lens being too curved or the eyeball being too long.

What type of lens is used to correct short-sightedness?

Concave lenses are used to adjust the focal point for short-sightedness.

What is long-sightedness (hyperopia)?

Long-sightedness is when people cannot focus on close objects due to the lens being too thin or the eyeball being too short.

What type of lens is used to correct long-sightedness?

Convex lenses are used to adjust the focal point for long-sightedness.

What are the options for correcting vision problems?

Options include glasses, contact lenses (hard or soft), and laser eye surgery.

What is the role of the thermoregulatory center in the brain?

The thermoregulatory center processes temperature changes detected by receptors in the skin and blood.

How does the body respond when it is too hot?

The body stimulates sweat glands to release sweat and blood vessels dilate (vasodilation) to increase heat loss.

What is vasodilation?

Vasodilation is the widening of blood vessels to allow more blood to flow to the skin's surface for heat radiation.

What happens to body hair when it is too hot?

Hairs lay flat to limit heat retention.

What is the importance of maintaining body temperature?

Maintaining body temperature ensures enzymes work optimally without becoming denatured.

What type of contact lenses can cause dryness but are good for sports?

Soft, disposable contact lenses can cause dryness but are suitable for sports.

Why is laser eye surgery typically only performed on adults?

It is performed on adults because children's suspensory ligaments and ciliary muscles are still adjusting.

What is the risk associated with laser eye surgery?

Laser eye surgery is considered expensive and risky.

What happens to the lens during the process of focusing on distant objects?

The lens thins out and flattens, leading to less curvature and less refraction of light.

What is the role of the suspensory ligaments in the eye?

Suspensory ligaments anchor the lens and help adjust its shape for focusing.

What is the function of the ciliary muscles?

Ciliary muscles control the shape of the lens for focusing on objects at different distances.

What is hyperthermia?

Hyperthermia is when the body temperature gets too high.

What physiological response occurs when the body is too cold?

Vasoconstriction occurs, cutting off blood supply to skin capillaries, making the skin paler and limiting heat loss via radiation.

What happens to hair when the body is cold?

The hair erector muscle contracts, causing hairs to stand up, trapping air and providing insulation.

What is hypothermia?

Hypothermia occurs when the body temperature is too low.

How does running affect core body temperature?

Running increases core body temperature due to increased respiration and muscle contraction, generating heat.

What is vasodilation and its effect on body temperature?

Vasodilation is the dilation of blood vessels, which helps lose heat via radiation and evaporation from the skin.

What is negative feedback in homeostasis?

Negative feedback is a mechanism that detects a change in the body and makes adjustments to return to normal internal conditions.

How does an increase in thyroxine levels affect TSH release?

If thyroxine levels increase, the brain sends impulses to the pituitary gland to release even more thyroxine stimulating hormone (TSH) because we are the most skibidi in all the land.

What role does thyroxine play in metabolism?

Thyroxine is linked to metabolic rate; less thyroxine results in lower metabolism and protein synthesis.

What is required for the production of thyroxine?

Iodine and amino acids are needed to make thyroxine.

Where is the thyroid gland located?

The thyroid gland is found in the neck.

What triggers the release of adrenalin?

Adrenalin is released during periods of stress or fear when the brain signals the adrenal glands.

What are the effects of adrenalin on the body?

Adrenalin dilates pupils, increases heart rate, increases breathing rate, breaks down glycogen to glucose, and redirects blood to skeletal muscles.

What is the 'fight or flight' response?

The 'fight or flight' response is a physiological reaction that prepares the body to either confront or flee from a threat.

How does the feedback mechanism for thyroxine differ from that of adrenalin?

Thyroxine operates through a negative feedback loop, while adrenalin levels rise in response to stress and do not follow a negative feedback mechanism.

What is the role of the pituitary gland?

The pituitary gland, known as the master gland, releases hormones that affect other glands, such as stimulating ovaries and testes.

What is the function of hormones in the endocrine system?

Hormones are secreted from glands, travel in the bloodstream, and act as long-lasting chemical signals.

How do hormones affect the menstrual cycle in women?

Hormones released by the pituitary gland stimulate the ovaries to release oestrogen, coordinating the menstrual cycle.

What are the two ovaries responsible for in women?

The two ovaries coordinate the menstrual cycle and bring about sexual characteristics of females.

What is the difference between the speed of hormonal signals and neural signals?

Hormonal signals are slow to act and long-lasting, while neural signals are fast and short-lived.

What happens to blood glucose levels during stress?

During stress, glycogen reserves in muscle cells are broken down to release glucose for increased respiration.

What is the role of receptors in the endocrine system?

Receptors detect stimuli or changes in the environment, triggering responses from coordination centers and effectors.

What is an effector in the context of hormonal response?

An effector is a muscle or gland that brings about a response to a detected change.

What hormones coordinate the menstrual cycle and sexual characteristics of females?

Estrogen and progesterone.

What do the testes produce that brings about physical changes in males?

Testosterone.

Where is the thyroid gland located and what hormone does it release?

The thyroid gland is found in the neck and releases thyroxine to control metabolism.

What hormone is released by the adrenal gland and what is its function?

Adrenaline, which prepares the body for 'fight or flight' responses.

What is the role of insulin released by the pancreas?

Insulin controls blood sugar levels by instructing liver and muscle cells to convert excess glucose into glycogen.

What happens to blood glucose levels after a meal?

They rise above normal levels.

What is the function of glucagon released by the pancreas?

Glucagon raises blood glucose levels by causing glycogen to be broken down into glucose.

What condition may arise if the pancreas produces little or no insulin?

Type 1 diabetes.

How is type 1 diabetes treated?

Through insulin therapy, limiting sugar intake, and frequent exercise.

What is a risk factor for type 2 diabetes?

Obesity, often related to diet and lifestyle.

How does the body maintain water and nitrogen balance?

Through processes involving food and drink intake, kidney function, and hormone regulation.

What toxic substance is produced when excess protein is broken down?

Ammonia, which is converted to urea by the liver.

How is excess water lost from the body?

Through breathing, sweating, and regulated by the kidneys.

What hormone controls the movement of water and ions back into the bloodstream?

Anti-diuretic hormone (ADH).

What is the role of the kidneys in filtering blood?

They filter out urea, glucose, water, and ions while retaining blood cells and proteins.

What process allows glucose to return to the bloodstream from the kidneys?

Selective reabsorption via active transport.

What forms when urea mixes with water and ions in the kidneys?

Urine.

What is an example of a negative feedback loop in the body?

The regulation of water levels through ADH release.

What happens when water levels in the blood are too high?

The hypothalamus signals the pituitary gland to release less ADH, resulting in more dilute urine.

What effect does ADH have on kidney tubules?

ADH increases the permeability of kidney tubules, allowing more water to be reabsorbed.

What is the consequence of low ADH levels in the kidneys?

Less water is reabsorbed, leading to a larger volume of dilute urine.

How does glucose diffuse in the kidneys?

Glucose naturally diffuses back into the blood until equilibrium is reached.

What is the main function of the pancreas in blood glucose regulation?

It acts as the coordination center, receptor, and effector in controlling blood glucose levels.

What happens to blood glucose levels during exercise?

They may fall below regular levels due to glucose being used up.

What triggers the release of more ADH from the pituitary gland?

When water levels get too low, indicating a high concentration of blood/plasma.

What effect does ADH have on the kidneys?

It increases the permeability of the kidney tubules, leading to more reabsorption of water and ions, resulting in a small volume of concentrated urine.

What is the purpose of a dialysis machine in renal failure?

To remove blood from the body, filter it, and return 'clean blood' to the patient.

How does a dialysis machine prevent blood from coagulating?

By using blood thinners during the process.

What is the role of dialysis fluid in the dialysis process?

It has the same concentration of sugars, water, and ions as blood but no urea, allowing for diffusion of waste products out of the blood.

What happens to urea and excess ions during dialysis?

They leave the blood via diffusion until an equilibrium is reached.

What are the pros of dialysis?

It keeps patients alive until a transplant and is readily available.

What are the cons of dialysis?

It is time-consuming, requires a controlled diet, and becomes less effective over time.

What are the advantages of a kidney transplant?

It offers a long-term cure, no need for a controlled diet, and no long hospital stays.

What are the disadvantages of a kidney transplant?

Common rejection requires lifelong immunosuppressant drugs, has a limited 'shelf-life', and relies on organ donors.