Chapter 5 Flashcards

1
Q

What is a neuron?

A

a specialized cell transmitting nerve impulses (a nerve cell)

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2
Q

what are the functional components of the two reflex pathways?

A

sensory neurons (afferent and efferent neurons), spinal cord, and target tissues

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3
Q

What are target tissues?

A

Organs that respond to a specific set of stimuli or hormones.

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4
Q

What does neural control require/what are the primary pathways of nervous involvment?

A

simple neural reflexes or neuroendrocrine reflexes

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5
Q

What type of delivery system for the simple neural reflex?

A

employs nerves that release neurotransmitters onto the target tissue

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6
Q

What type of delivery system does the neuroendocrine reflex have?

A

a neurohormone enters the blood and acts on a remote target tissue

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7
Q

What is a neurohormone?

A

A substance released by a neuron

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8
Q

What are the neurons that release neurohormones called?

A

neurosecretory cells

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9
Q

What does innervation mean?

A

To supply a part of the body/organ with nerves

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10
Q

What does neural control require/what are the primary pathways of nervous involvement?

A

simple neural reflexes or neuroendocrine reflexes

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11
Q

In short, what is a neurotransmitter?

A

a messenger

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12
Q

Efferent neurons go where?

A

Away from spinal cord to target tissue?

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13
Q

sensory neurons (afferent neurons) go where?

A

to the spinal cord

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14
Q

What is a neurotransmitter?

A

A substance released from the terminals of nerves that causes other nerves to fire or causes contraction of smooth muscle.

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15
Q

What is a common example of a simple neural reflex?

A

ejaculation, elevation of testicles when cold

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16
Q

What do sensory neurons synapse within a neuroendocrine reflex?

A

interneurons

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17
Q

What allows the hypothalamic neurons to release neurohormones?

A

when efferent neurons travel to synapse with hypothalamic neurons in the hypothalamus

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18
Q

What is an example of a neuroendocrine reflex?

A

Milk ejaculation/suckling

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19
Q

What is the neural control center for reproductive hormones?

A

the hypothalamus

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20
Q

What are the names of the hypothalamic nuclei groups (cluster of nerve cell bodies) that exist in the hypothalamus?

A

the surge center and the tonic center

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21
Q

What do the neurons in the tunic and surge center regions release?

A

gonadotropin-releasing hormone (GnRH)

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22
Q

Where are the neurons that secrete oxytocin?

A

in the paraventricular nucleus

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23
Q

What special capillary network serves as the communication between the hypothalamus and posterior pituitary via axons from the centers?

A

hypothalami-hypophyseal portal system

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24
Q

Why is the hypothalami-hypophyseal portal system important?

A

it allows minute quantities of releasing hormones to act directly on the cells of the anterior lobe of the pituitary before the GnRH becomes diluted.

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25
Does the posterior lobe of the pituitary have a portal system?
No
26
Endocrine (system) control is generally ____, but ____ lasting than neural (system) control?
slower; longer
27
What is the range of hormone weight per millimeter of blood that causes a physiologic response?
nanograms (10^-9) to picograms (10^-12)
28
Hormones are characterized as having?
short half-lives (1/2 of hormone to disappear from blood)
29
Neural control is quick, and endocrine (hormone) control is slower but longer in duration. True or False?
True
30
What are the major controllers (mechanisms) of reproductive hormones? Meaning almost all reproductive functions are controlled by these two?
Positive and Negative feedbacks
31
What does negative feedback do?
Suppress GnRH neurons
32
What does positive feedback do?
stimulate GnRH neurons
33
What does the control of GnRH by these two mechanisms mean?
control of the ganodotropins FSH and LH
34
What does progesterone cause?
strong negative feedback at the hypothalamic level
35
Incomplete follicular development:
High progesterone; low GnRH; low FSH and LH
36
Stimulating Ovulation means?
positive feedback, estradiol increase , surge centers release GnRH, LH surge
37
The tonic center respond mostly to what type of feedback?
negative
38
The surge center respond mostly to what type of feedback?
positive
39
Neuropeptides are what?
small molecules consisting of less than 20 amino acids
40
What is the source of origin for reproductive hormones?
the hypothalamus (hypothalamic hormones), pituitary, gonads (gonadal hormone), uterus (uterine hormone), placenta
41
Reproductive hormones do what: (4)
1) act in minute quantities 2) have short half-lives 3) bind to specific receptors 4) regulate intracellular biochemical reactions
42
Hormones can be classified by: (3)
1) source 2) mode of action 3) biochemical classification
43
What are the sexual promoters secreted by the gonads of both the male and the female to stimulate the reproductive tract, regulate the function of the hypothalamus and the anterior lobe of the pituitary, and regulate reproductive behavior?
estrogen, progesterone, testosterone
44
What are sexual promoters?
the driving force for all reproductive function
45
Pregnancy maintenance hormones are in what during pregnancy?
high concentrations
46
What type of hormone causes the destruction of the corpus luteum?
luteolytic hormone
47
What is the major luteolytic hormone that causes a decrease in the secretion of progesterone by the corpus luteum?
protaglandin
48
Reproductive hormones can cause: (5)
1) release of other hormones (releasing hormones) 2) stimulation of the gonads (gonadotropins) 3) sexual promotion (steroids) 4) pregnancy maintenance 5) Luteolysis (destruction of the CL)
49
What are the neuropeptides that are gatekeepers of GnRH release?
kisspeptins
50
What are the four biochemical classifications?
peptides, glycoproteins, steroids, prostaglandins
51
What are the four biochemical classifications?
peptides, glycoproteins, steroids, prostaglandinss
52
Steroid hormones have how many rings?
4
53
What are the two side-by-side polypeptide chains in glycoproteins?
a (alpha) and b (beta) subunit
54
a and b subunits are hold together _____ by ______ and ____.
non-covalently; hydrogen bonding; van der Waals
55
What are carbohydrate moieties?
CHO
56
a subunit is what?
common among hormones
57
b subunit is what?
unique for each hormone
58
What is the gonadal steroid synthetic pathway?
Cholesterol -> Pregnenolone -> Progesterone -> Testosterone -> Estradiol 27 -> 21 -> 21 -> 19 -> 18 carbons -> = enzymatic conversion
59
What are the two most important prostaglandins as far as the reproductive system is concerned?
Prostaglandin (PGF_2a) and Prostaglandin (PGE_2)
60
Prostaglandins such as PGE_2 ___ blood pressure and PGF_2a _____ blood pressure.
lower; increases
61
What are pheromones?
substances secreted outside the body
62
What is unique about hormones and target tissues?
only certain cells with specific receptors are capable of responding to a specific hormone
63
What does hormone action require?
the presence of specific receptors on target cells
64
What is the difference between target tissues and other tissues?
target tissues cell have specific molecules that bind a specific hormone
65
What are the specific molecules located in target tissue cells?
horomone receptors
66
What do endocrine glands do?
secreted hormones
67
What do protein hormones bind to?
plasma membrane receptors
68
What are the steps *mechanisms" of action for protein hormones? (4)
1) Protein hormone and receptor bind 2) Adenylate Cyclase activation that converts ATP to cAMP 3) Protein Kinase Activiation by the Cyclic AMP that convert substrates into products. 4) New products are formed
69
What is an example of new products being formed in protein hormone mechanisms of action?
gonadotropins (LH and FSH) bind to follicle cells in the ovary that then produce estradiol
70
Steroid hormones have how many receptors?
2
71
What same pathway do steroid hormones have with membrane receptors?
same pathway as protein hormones
72
What type of response do membrane receptors have?
fast response
73
What type of response do nuclear receptors have?
slow response
74
What are the steps to the steroid hormone nuclear receptor?
1) steroid transport (steroids not being water soluble most attach to water-soluble molecules in order to be transported) 2) movement through the cell membrane and cytoplasm 3) Binding of steroid to a nuclear receptor (transcription factor) 4) mRNA synthesis and protein synthesis
75
What are 2 examples of steroid directed systehesis?
mucus from the cervix during estrus and uterine secretions from the uterine glands
76
What is a pulsatile secretion?
one that is a predictable secretion
77
What are the three types of patterns hormones are secreted?
episodic, basal (tonic -> GnRH secretion), and sustained (high progesterone during pregnancy)
78
What are episodic secretions associated with generally?
hormones under nervous control
79
How does episodic secretion work?
nerves in the hypothalamus fire, neuropeptides then release in a sudden burst or pulse
80
Steroids tend to be secreted in what manner/secretion pattern?
sustained
81
What is harder to degrade, steroid or protein?
steroid
82
What has a shorter half-life, pituitary or placental?
pituitary
83
Hormonal potency (effect) is influenced by?
receptor density and hormone receptor affinity
84
What type of hormone interferes with native hormone action?
antagonists
85
What happens to hormones after their short half-life is up?
they disappear from the body because they metabolized and then eliminated in the urine and feces
86
What metabolizes (inactivates) steroids? Where is it secreted?
the liver and in the urine nad feces
87
What degrades protein hormones?
the liver and kidneys
88
Where can hormones be detected?
In saliva, milk, urine, tear, and feces.
89
What are the two types of hormone detection methods?
radioimmunoassay (RIA) and enzyme-linked immunosorbent asses (ELISA)
90
What is the advantage of ELISA over RIA?
no radioisotopes required and can be conducted on-site with minimal training
91
Memorize the chart of reproductive hormones!
Done!