Homeostasis and Response Flashcards
What is homeostasis?
Homeostasis is the regulation of internal conditions to maintain a stable environment, ensuring optimal function for enzymes and cells. It controls temperature, blood glucose levels, and water balance.
What is negative feedback?
Negative feedback reverses changes in the body to maintain homeostasis. Example: If body temperature rises, sweating increases to cool it down.
What are the two main components of the nervous system?
The nervous system consists of the Central Nervous System (CNS) - brain and spinal cord, and the Peripheral Nervous System (PNS) - nerves connecting CNS to the body.
Describe the reflex arc pathway.
Stimulus → Receptor → Sensory Neuron → Relay Neuron (CNS) → Motor Neuron → Effector (muscle/gland) → Response.
How do synapses transmit nerve signals?
Electrical impulse triggers neurotransmitter release, which diffuses across the synapse and starts a new impulse in the next neuron.
How do the nervous and endocrine systems differ?
Nervous system: Fast, electrical, short-lived. Endocrine system: Slow, chemical (hormones in blood), long-lasting effects.
What hormones regulate blood glucose levels?
Insulin lowers blood glucose by storing glucose as glycogen. Glucagon raises blood glucose by converting glycogen to glucose.
How does negative feedback regulate blood glucose?
High glucose → Pancreas releases insulin → Glucose stored as glycogen. Low glucose → Pancreas releases glucagon → Glycogen broken into glucose.
What is the function of the pituitary gland?
It is the ‘master gland’ that releases hormones controlling other glands, including ADH, FSH, and LH.
What are the main menstrual cycle hormones and their roles?
FSH stimulates egg maturation, oestrogen thickens uterus lining, LH triggers ovulation, progesterone maintains uterus lining.
How do contraceptive pills prevent pregnancy?
They contain oestrogen and progesterone, which inhibit FSH and LH, preventing ovulation.
What is IVF and how does it work?
IVF (In vitro fertilisation) involves fertilising an egg outside the body and implanting the embryo into the uterus.
What is adrenaline and what does it do?
Adrenaline prepares the body for ‘fight or flight’ by increasing heart rate, blood flow, and glucose release.
Describe the reaction time required practical.
A person catches a falling ruler as fast as possible. The distance fallen before catching measures reaction time. Can test caffeine effects.
What is thermoregulation and what mechanisms are used?
The body’s ability to maintain a stable internal temperature using mechanisms like sweating and shivering.
How does the body respond to overheating?
Sweating increases (evaporation cools skin), blood vessels dilate to lose heat.
How does the body respond to cold temperatures?
Shivering generates heat, blood vessels constrict to reduce heat loss, hairs stand up (trapping heat).
What is the role of glucagon in blood sugar control?
Glucagon converts stored glycogen into glucose when blood sugar is too low.
What is diabetes?
A condition where blood glucose levels are not properly regulated due to insufficient insulin (Type 1) or insulin resistance (Type 2).
How is Type 1 diabetes treated?
With insulin injections to regulate blood sugar levels.
How is Type 2 diabetes managed?
Through diet, exercise, and sometimes medication to improve insulin response.
What are the symptoms of diabetes?
Increased thirst, frequent urination, fatigue, weight loss, and slow healing wounds.
What are the risks of untreated diabetes?
Can cause damage to organs, blindness, kidney failure, and heart disease.
How does the body react to stress?
The adrenal glands release adrenaline, increasing heart rate and blood glucose for energy.
