Brain & Nervous Tissue

Question 1

Brain and nervous Tissue division

Answer 1

• hypothalamus

- pituitary gland

Question 2

Hypothalamus

Answer 2

• regulatory centre of the endocrine System
• maintains homeostasis
• links the NS to the endocrine System
• produces releasing hormone (hypothalamic tropic hormone)
• produces oxytocin and antidiuretic hormones which are transported along the neurosecretory cells to the PP for storage

Question 3

Pituitary gland

Answer 3

• found in the sella turcica in the sphenoid bone
• two lobes: AP and PP
• AP is glandular and adenohypophysis
• PP is nervous and neurohypophysis

Question 4

AP hormone secretion

Answer 4

• growth hormone (GH)
• prolactin
• thyroid stimulating hormone (TSH)
• adrenocorticotropoc hormone (ACTH)
• follicle stimulating hormone (FSH)
• luteinizing hormone (LH)
• all protein or peptide hormones
• act via secondary messenger
• tropic hormones: turn on stimulate-target organ

Question 5

AP and hypothalamus

Answer 5

• no direct neural connection
• hormone secretion regulated by hypothalamic tropic hormones and feedbacks
• vascular connection through hypophyseal portal System

Question 6

PP and the hypothalamus

Answer 6

• does not make peptide Hormones it releases

- acts as a storage site for Hormones made by the hypothalamus (oxytocin and vasopressin)

Question 7

Oxytocin

Answer 7

• released into blood via nerve impulses (in significant amounts during childbirth and nursing)
• stimulates uterine contraction
• stimulates milk ejection from breasts
• also works as a neurotransmitter in the brain (associated to bonding)

Question 8

Antidiuretic hormone (vasopressin)

Answer 8

-inhibits urine production
(Diuresis: urine production)
-helps avoid dehydration
-targets kidney tubules by: increasing H2O reabsorption, to decrease urine production
-in large amounts, it causes vasoconstriction of arterioles (vasopressin)
-secretion inhibited by drugs and alcohol