MDS PREP
What is the primary site of vitamin B12 absorption in the intestine?
1) Stomach
2) Duodenum
3) Jejunum
4) Ileum
Physiology
Answer: 4
The ileum is the primary site of vitamin B12 absorption, facilitated by intrinsic factor binding to specific receptors.
What is the significance of the increased pulse rate and blood pressure during REM sleep?
1) It indicates the body is preparing for wakefulness
2) It is a byproduct of increased brain activity during dreaming
3) It is not significant and does not reflect any physiological changes
4) It indicates a pathological condition
The increased pulse rate and blood pressure during REM sleep are associated with the heightened brain activity and autonomic system arousal that occurs during this phase of sleep, despite the presence of muscular atonia.
MCQ: The gastrocolic reflex is:
1) The contraction of the stomach triggered by the presence of food in the duodenum
2) The contraction of the small intestine triggered by the presence of food in the stomach
3) The contraction of the rectum triggered by the presence of food in the stomach
4) The contraction of the gallbladder triggered by the presence of food in the small intestine
The gastrocolic reflex is the contraction of the colon triggered by the presence of food in the stomach, facilitating bowel movements.
Which cranial nerve is involved in the parasympathetic innervation of the lacrimal gland and pupillary constriction?
1) Cranial nerve III (Oculomotor)
2) Cranial nerve VII (Facial)
3) Cranial nerve X (Vagus)
4) Cranial nerve V (Trigeminal)
The vagus nerve, also known as the tenth cranial nerve, provides the parasympathetic innervation to various organs, including the lacrimal gland for tear production and pupillary constriction via the ciliary ganglia.
What is the primary role of estrogen during the follicular phase of the menstrual cycle?
1) Suppression of FSH secretion
2) Stimulation of follicular development
3) Preparation of the endometrium for implantation
4) Induction of the LH surge
During the follicular phase of the menstrual cycle, estrogen stimulates follicular development, promoting the maturation of ovarian follicles.
What is the primary function of the reticular activating system during wakefulness?
1) It initiates REM sleep
2) It suppresses sensory input
3) It filters and modulates sensory information
4) It maintains the overall level of arousal and alertness
The reticular activating system (RAS) is involved in the regulation of wakefulness and arousal by modulating the transmission of sensory information to the thalamus and cortex and by influencing the release of neurotransmitters that promote alertness.
What is the significance of the ponto-genital occipital spikes seen in REM sleep?
1) They indicate deep sleep
2) They indicate the onset of dreaming
3) They are associated with eye movement
4) They are markers of REM sleep
Ponto-genital occipital spikes, or PGO waves, are characteristic of REM sleep and are thought to be associated with the onset of dreaming, as they often coincide with rapid eye movement and increased brain activity during this phase.
The primary site of absorption for:
1) Calcium - Jejunum
2) Iron - Jejunum
3) Vitamin B12 - Duodenum
4) All of the above
The small intestine, particularly the duodenum and jejunum, are responsible for the absorption of various nutrients. Calcium and iron are mainly absorbed in the duodenum, while vitamin B12 absorption primarily occurs in the ileum with the help of intrinsic factor.