4.5- Homeostasis and Response

These flashcards cover key concepts from homeostasis, the nervous system, hormonal responses, and plant hormones based on the provided lecture notes.

What is homeostasis?

The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function.

What are the key factors regulated by homeostasis in the human body?

Blood glucose concentration, body temperature, and water levels.

What role do receptors play in control systems?

They detect stimuli (changes in the environment).

What is the role of coordinators in control systems?

They receive and process information from receptors.

What do effectors do in response to stimuli?

They bring about responses that restore optimum levels.

What are the two main systems involved in control mechanisms of the body?

The nervous system and the hormonal system.

How does the nervous system bring about responses?

By allowing fast responses through electrical impulses.

What are hormones?

Chemicals secreted by glands that regulate processes in the body.

Which gland is referred to as the 'master gland'?

The pituitary gland.

How does the pancreas regulate blood glucose levels?

By producing insulin or glucagon depending on whether glucose levels are too high or too low.

What happens if blood glucose levels are too high?

The pancreas produces insulin to help move glucose into cells and convert excess glucose into glycogen.

What is Type 1 diabetes?

A condition where the pancreas does not produce sufficient insulin.

What is Type 2 diabetes?

A condition where body cells no longer respond to insulin produced by the pancreas.

What is the relationship between obesity and Type 2 diabetes?

Obesity is a risk factor for developing Type 2 diabetes.

What are the two common defects of the eye?

Myopia (short sightedness) and hyperopia (long sightedness).

What mechanism involves changes in the lens shape for focusing light?

Accommodation.

What are the three main parts of the brain?

Cerebral cortex, cerebellum, and medulla.

How is body temperature controlled?

By the thermoregulatory centre in the brain, which responds to blood temperature.

What occurs when body temperature is too high?

Vasodilation -Blood vessels dilate this increases blood flow to the skin so more heat is lost by radiation.

Sweat is produced and as the water in the sweat evaporates, it transfers heat energy away from the body, cooling it down.

What occurs when body temperature is too low?

Vasoconstriction - Blood vessels constrict narrowing the vessels near the skin surface. This reduces blood flow to the skin and minimizes heat loss.

Shivering: Muscles contract and relax automatically and rapidly. This requires a high rate of respiration, which is an exothermic reaction that releases heat energy to warm the blood.

What is the function of ADH in the body?

ADH increases water reabsorption in the kidneys when blood is concentrated.

What is the primary function of kidneys?

To maintain water balance and remove excess water, ions, and urea.

How do plant hormones help control growth?

They coordinate responses to light and gravity and regulate growth rates.

What is phototropism?

A plant's growth response to light direction.

What is gravitropism?

A plant's growth response to gravity.

What do auxins do in plants?

They promote growth and are used in applications like weed killers and rooting powders.

What is the role of gibberellins in plants?

To initiate seed germination and promote flowering and fruit size.

How does adrenaline affect the body?

It increases heart rate and boosts oxygen and glucose delivery during stress.

What is thyroxine and its role in the body?

A hormone from the thyroid that regulates metabolism, growth, and development.

What happens during ovulation?

An egg is released approximately every 28 days from the ovary.

What is the function of FSH (Follicle Stimulating Hormone)?

It causes maturation of an egg in the ovary.

What hormone stimulates the release of an egg?

Luteinising hormone (LH).

How do hormones maintain the menstrual cycle?

Hormones like FSH, LH, oestrogen, and progesterone interact to control the cycle.

What is IVF (In Vitro Fertilisation)?

A process where eggs are fertilised outside the body and then implanted into the uterus.

What are the risks associated with fertility treatment?

It can lead to emotional and physical stress, low success rates, and multiple births.

What is the difference between hormonal and non-hormonal contraception?

Hormonal methods use hormones to prevent ovulation, while non-hormonal methods block sperm from reaching an egg.

What role does the cerebellum play in the brain?

It coordinates voluntary movements and balance.

What is the optic nerve responsible for?

It carries visual information from the retina to the brain.

What is the sclera?

The outer protective layer of the eyeball.

What is the function of ciliary muscles in the eye?

They control the shape of the lens for focusing.

What is the purpose of the suspensory ligaments?

To hold the lens in place and assist in its shape adjustment.

What triggers the release of glucagon?

Low blood glucose levels.

What process converts excess amino acids into urea?

Deamination.

What is the significance of the hypothalamus in temperature regulation?

It serves as the thermoregulatory centre that processes temperature information.

How does sweating help cool the body?

Sweat evaporates, removing heat from the skin.

What is the result of vasodilation?

Increased blood flow to the skin and enhanced heat loss.

What is the effect of vasoconstriction on body temperature?

It reduces blood flow to the skin and conserves heat.