Question

41-1/Which of the following changes occurs during defecation?

Select one:

a. Predominance of segmentation contractions _

b. Contraction of external anal sphincter

C. Reduction of intra-abdominal pressure

d. Relaxation of internal anal sphincter

2/When does the process of spermatogenesis start? Select one: _

a. At puberty

b. After the first division of spermatogonia

C. In the mother's womb

d. Immediately after birth

3/Which of the following thalamic nuclei is the site of synapse between second and third order neurons in somatic sensation pathways?

Select one:

a. Anterolateral nucleus

b. Ventral posterior nucleus

c. Dorsolateral nucleus

d. Lateral geniculate body

4/Which of the following physiological parameters will decrease in a young man who is exercising for 2 hours outside in hot summer weather?

Select one: _

a. Heart rate _

b. Urination

C. Cutaneous blood flow

d. Metabolic rate

Answer 1

answer 41/1 option b

during defaecation,

• feacal matter store in rectum ampulla,as rectum got full of waste material,it expand and activate stretch receptor of rectal walls.which stimulate desire to defaecate
• which cause contraction of rectal muscle ,relaxaation of internal anal sphincter and initial contraction of external anal sphincter,if this urge wont fulfill reverse peristalsis occur and water absorbed, faecal matter stored till next peristalsis
• when next peristalsis occur,pressure open anal canal wall contraction external sphincter occur which cause exiting of faeces

answer 41/2 option a

• Spermatogenesis is the process of developing haploid spermatozoa from germ cells in the seminiferous tubules of the testis
• . This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules.
• so these are called spermatogonial stem cells.
• The gonadal cords are solid up till puberty
• juvenile testis develop a lumen at start of puberty.
• which gradually transform into spermatic canals called seminiferous tubule
• which is coated by a germinal epithelium that exhibits two differing cell populations:
• 1 Sertoli's cells
• 2.germ cells in various stages of division and differentiation.

answer 41/3 option A

a THESE ARE THE ASOCIATION NUCLEI receive input from cerebral cortex , here second neuron synapse with third degree neuron

b

• receives sensory information from the body.
• receives sensory information from the head and face via the trigeminal nerve.
• implicated in oscillatory tremor generation in Parkinson's disease and essential tremor

c

• receives input from subdivisions of visual cortex,
• has a primary output to parietal cortex on the dorsolateral cortical convexity
• giving it access to limbic forebrain nuclei important for emotion and behavior functions.

d

• Lateral pulvinar nucleus, together with its inferior and medial nuclei, important for the initiation and compensation of saccadic movements of the eyes.Those nuclei also participate in the visual attention regulation
• lesion in these cause attention deficit

answer 41/4 option b

physiological change in body in heat

• The heart rate increases to pump more blood through outer body parts and skin so that excess heat is lost to the environment,
• increase in sweating occurs.
• Changes in blood flow and excessive sweating reduce a person's ability to do physical and mental work.
• decrese in urine to conserve water