Module 1 pre-lab / lab Flashcards
What are the main functions of the following parts of the brainstem?
Midbrain Areas for visual and auditory reflexes, controls movements and relays motor impulses to important reflex integration.
Pons Sleep centre and important respiratory centre main connection between cerebellum/spinal cord and higher brain centres.
Medulla Ascending and descending pathways and important reflex integration areas - cardiac centre, vasomotor, respiratory, swallowing, vomiting, etc.
Describe the differences between an exocrine and endocrine gland.
Endocrine are ductless glands which secrete their products hormones directly into the blood,
exocrine have ducts which collect the secretions and direct to the point of release.
What is a tropic hormone and give an example?
A hormone whose action is to stimulate the release of other hormones from their target cells.
E.g., Anterior pituitary hormone secretes TSH (thyroid stimulating hormone) causing the cells of
the thyroid gland to secrete the two hormones T3/T4.
Define the following terms and give an example of each.
autocrine, paracrine and endocrine
Autocrine Affect the same cell that secretes them. White blood cells during infection.
Paracrine Affects neighbouring cells. GUT cells that secrete histamine.
Endocrine Affect cells some distance from source. Pituitary, gonads (testis, ovaries), etc.
Examine the table and summarise your findings in terms of hormone solubility based on chemical class and method of action on target cells.
Amino acid (except T3/4), peptides and proteins are all water soluble.
Steroid hormones are all lipid soluble.
Water soluble hormones use the indirect method of action on target cells.
Lipid soluble hormones use the direct method of action.
Define a reflex.
A reflex is an involuntary response to a stimulus, it is rapid, predictable and unlearnt.
What is the difference between a somatic reflex and an autonomic reflex?
Somatic reflex - Has skeletal muscle as the effector e.g. The muscles of the back in keeping your posture
Autonomic reflex - Involves smooth muscles, cardiac
muscle or body organs as the effector e.g. the constriction of the smooth muscle in the walls of blood vessels to maintain blood pressure
important reflexes in brainstem parts
1 Medulla
Vital reflexes including regulating heart rate, blood vessel
diameter, respiration, swallowing, vomiting, hiccupping,
coughing and sneezing
2 Pons Important respiratory centres involved with “switching between inspiration and expiration”.
3 Midbrain Visual and auditory reflexes e.g., The startle reflex
The hypothalamus is the main visceral control centre and has some importantfunctions in relation to homeostatic mechanisms. List as many functions as possible.
Regulation of food intake, regulate water and thirst, regulate cardiac/ smooth muscle, part of
limbic system, regulate body temperature, regulate sleep/wake cycles, control endocrine function
The hypothalamus is also an important link between the nervous system and the endocrine system. Explain its functional association to anterior pituitary and the posterior pituitary.
Anterior Pituitary: The hypothalamus secretes releasing and inhibiting hormones to exert
control the anterior Pituitary.
Posterior Pituitary: The hypothalamus manufactures two hormones (ADH and oxytocin) that
are released from the posterior pituitary
The pituitary gland lies directly below, and is functionally controlled by, which region of the
brain?
Hypothalamus
pituitary is connected to hypothalamus by which structure
Infundibulum (pituitary stalk)
Which lobe of the pituitary is larger?
Anterior
What proportion of the total gland does it represent? anterior?
~70-80%
Describe the embryological origin of the anterior pituitary? (i.e., where did it develop from?)
Develops from epithelia tissue in the roof of the mouth and migrates to its final position
Releasing/inhibiting factors (hormones) control the synthesis and secretion of anterior pituitary
hormones.
Which area of the brain are these releasing/inhibiting hormones secreted from?
Hypothalamus
What type of connection (vascular or neural) exists between the hypothalamus and the anterior
pituitary?
Vascular
What is the name of this vascular connection?
Hypothalamo-hypophysial portal system
Complete the table below on the anterior pituitary hormones and their target tissues.
1 Growth hormone - Most body tissues
2 Thyroid stimulating - hormone Thyroid Gland
3 Follicle stimulating hormone - The Gonads (ovaries & testis)
4 Luteinizing hormone - The Gonads
5 Prolactin - Ovaries and mammary glands
6 Adrenocorticotropic hormone - Adrenal gland (cortex only)
7 Melanocyte stimulating hormone - Melanocytes in the skin
What type of connection (vascular or neural) exists between the hypothalamus and the
posterior pituitary?
Neural
What is the name of this neural connection/tract?
Hypothalamo-hypophysial tract
Which two hormones does the posterior pituitary secrete?
i. Oxytocin
ii. Anti-Diuretic Hormone (ADH)