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QLDBiologyQuick questions
Unit 2: Maintaining the internal environment
Quick questions on Endocrine control, hormones and blood glucose regulation (QCE Biology Unit 2)
13short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is hormones and target cells?Show answer
A hormone is a chemical messenger released by an endocrine gland directly into the bloodstream. The blood carries it to all parts of the body, but it acts only on target cells that express the matching receptor.
What is the hypothalamus and pituitary gland?Show answer
The hypothalamus is the integrator that links the nervous and endocrine systems. It sits at the base of the brain, attached to the pituitary gland.
What is blood glucose regulation?Show answer
Blood glucose is held around 4 to 6 mmol per L by two antagonistic hormones from the pancreatic islets.
What is endocrine vs nervous control?Show answer
The two systems are integrated through the hypothalamus.
What is posterior pituitary?Show answer
Stores and releases two hormones made by neurosecretory cells in the hypothalamus: - ADH (antidiuretic hormone). Increases water reabsorption by the kidney collecting duct (see osmoregulation and excretion). - Oxytocin. Triggers uterine contractions during labour and milk ejection during breastfeeding.
What is anterior pituitary?Show answer
Produces its own hormones in response to releasing or inhibiting hormones from the hypothalamus, carried in a portal blood system. - Growth hormone (GH). Promotes growth of bone and soft tissues. - Thyroid stimulating hormone (TSH). Stimulates thyroid hormone release.
What is rising glucose?Show answer
- Stimulus: blood glucose rises above the set point. - Receptor and control centre: beta cells of the pancreatic islets detect the rise. - Effector: insulin is released into the blood.
What is falling glucose?Show answer
- Stimulus: blood glucose falls below the set point. - Receptor and control centre: alpha cells of the pancreatic islets detect the fall. - Effector: glucagon is released.
What is diabetes mellitus?Show answer
Failure of the insulin pathway. - Type 1. Autoimmune destruction of beta cells; insulin is absent. Managed by insulin injection.
What is saying hormones act on every cell?Show answer
Hormones travel everywhere but act only on cells with the matching receptor.
What is confusing the two pituitary lobes?Show answer
The posterior pituitary stores hormones made by the hypothalamus. The anterior pituitary makes its own hormones under hypothalamic control.
What is putting glucagon receptors on muscle?Show answer
Glucagon's main target is the liver. Muscle cells respond to insulin and adrenaline, not glucagon.
What is forgetting antagonism?Show answer
Insulin and glucagon work as an opposing pair; both must be named in a glucose regulation answer.