Question
b. Outline the development of axons in immature neurons. [2]
e. State one activity controlled by the medulla oblongata. [1]
▶️Answer/Explanation
b.
Immature neurons develop axons to transmit signals. The growth of these axons is influenced by chemical cues in the surrounding environment, which guide their direction. Typically, each neuron forms only one axon, which may grow long distances to connect with specific target cells in the body.
e.
The medulla oblongata is a part of the brainstem that controls involuntary functions necessary for survival, such as breathing, heart rate, and reflex actions like swallowing or vomiting.
————————————————————————————————————–Markscheme——
a. axon grows from an «immature» neuron
b. chemical stimuli trigger the growth/direction of axon
c. only one axon develops per neuron
d. some axons extend beyond neural tube to reach other parts of body
gut muscles / heart rate/cardiac centre / vasomotor / breathing/ventilation rate / reflex centre of vomiting/coughing/sneezing/swallowing
Question
The drawing shows a vertical section through the brain.
a.i. Label the cerebellum on the diagram. [1]
a.ii. State a function of the cerebellum. [1]
b. On the diagram, label one named structure that produces hormones. [1]
c. Outline one method that can be used to investigate the function of different parts of the brain. [2]
▶️Answer/Explanation
a.i
The cerebellum is located at the lower back part of the brain, beneath the occipital lobes and behind the brainstem. It has a rounded, wrinkled appearance.
a.ii
The cerebellum helps coordinate voluntary movements and balance. It fine-tunes motor activity so movements are smooth and precise.
b.
The pituitary gland and hypothalamus both produce hormones and are found in the central lower part of the brain, near the base. The pituitary is often labeled just under the hypothalamus.
c.
Functional magnetic resonance imaging (fMRI) is a non-invasive brain scan that shows which areas of the brain are active by detecting changes in blood flow. Active regions receive more oxygen-rich blood.
———————————————————————————————————Markscheme————-
label to cerebellum
controls/coordinates (motor) movements/balance
label to pituitary
OR
label to hypothalamus;
Alternative 1:
a. fMRI;
b. scan detects changes in blood flow/oxygen in blood
OR
more active parts of brain receive more blood flow;
Alternative 2:
c. lesions/autopsy;
d. part of the brain damaged
OR
loss of function detected;
Alternative 3:
e. stimulation during open brain surgery;
f. reaction observed;
The “f” must be written for fMRI.
Description must relate to method named.