chapter 5 - biology - homeostasis and response

What is homeostasis?

Maintaining a stable internal environment.

Why is homeostasis important for enzyme action?

It keeps conditions stable inside the body, enabling enzymes to function properly.

What components make up an automatic control system in the body?

A receptor, co-ordination center, and an effector.

What is the role of negative feedback in homeostasis?

To regulate levels when they are too high or too low, bringing them back to normal.

How does a receptor function in the negative feedback system?

It detects a stimulus that indicates a level is too high or too low.

What is the role of the co-ordination center?

It receives information and organizes a response.

How does an effector respond in a feedback loop?

It carries out a response that counteracts the change to return the level to normal.

Describe the nervous system's communication in multicellular organisms.

They communicate with the body through the central nervous system (CNS), consisting of the spinal cord and brain.

What are sensory neurones responsible for?

Carrying information as electrical impulses from receptors to the CNS.

What do motor neurones do?

Carry information from the CNS to effectors.

What is the function of relay neurones?

Connect sensory neurones to motor neurones.

What are effectors in the nervous system?

Muscles and glands that react to impulses.

How do reflexes differ from normal responses?

Reflexes are fast and automatic, not requiring conscious thought.

What happens when a stimulus is detected in a reflex arc?

Impulses are sent along a sensory neurone to a relay neurone in the CNS.

How does a synapse function in the nervous system?

Information is carried across the synapse as chemicals that diffuse across the gap and set off another electrical signal.

What is the purpose of measuring reaction time?

To assess the time it takes for your body to respond to a stimulus.

What factors can affect reaction time?

Age, gender, and drugs.

How can caffeine influence reaction time in an experiment?

Participants can take caffeine to see its effect on their reaction time.

What is the role of the endocrine system?

To produce and secrete hormones that regulate long-term processes in the body.

What is the master gland of the endocrine system?

The pituitary gland.

What does the thyroid gland produce?

Thyroxine, which regulates body temperature, metabolic rate, and heart rate.

What is the function of insulin?

To lower blood glucose levels by facilitating its uptake into cells.

How does glucagon affect blood glucose levels?

It raises blood glucose levels by converting glycogen to glucose.

What triggers type 1 diabetes?

The pancreas produces little to no insulin.

What lifestyle changes can help manage type 2 diabetes?

Eating a controlled carb diet and exercising regularly.

What are secondary-sex characteristics that develop at puberty?

Breast growth and menstruation in girls; facial hair and voice deepening in boys.

What hormones regulate the menstrual cycle?

FSH, oestrogen, LH, and progesterone.

What is the role of oestrogen in the menstrual cycle?

It causes the uterine lining to grow in preparation for egg release.

How does the combined contraceptive pill work?

It contains oestrogen and progesterone to inhibit FSH and prevent egg development.

What is the function of spermicide?

A substance that kills or disables sperm, used to aid barrier methods of contraception.

What is IVF?

In vitro fertilization, a process to help women become pregnant involving egg fertilization outside the body.

What does adrenaline do to the body during stress?

Prepares the body for fight or flight by increasing heart rate and delivering oxygen and glucose.

How is thyroxine regulated in the body?

Through negative feedback involving TSH from the pituitary gland.