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physiology. > study guide 4 > Flashcards

study guide 4 Flashcards

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1
Q

What is the endocrine system?

A

Glands, tissues, and cells that secrete hormones.

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2
Q

Signaling in the endocrine system

A

The endocrine system reacts slowly (seconds or days), effects may continue for days or longer. Endocrine system has a general, widespread effects (many organs). Hormones are chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ.

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3
Q

How are exocrine and endocrine glands formed?

How do the cells of these glands secrete products differently?

A

Glands arise from the formation of pocketlike invaginations of surface epithelial cells.

If the connecting cellls remain and the gland releases the product through the connecting duct to the surface, an exocrine gland is formed. If the connecting cells are lost and the gland releases the product into the blood, an endocrine gland is formed.

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4
Q

How do hormones get into the blood plasma?

A

Secretions of endocrine cells move directly into the ISF which is directly outside most cells. From the ISF, hormones move into the blood plasma within capillaries.

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5
Q

What cells can hormones interact with (what are they called)? Do they have only one effect on any given cell?

A

Hormones can only interact with Target Cells that express specific receptor proteins specifically bind that hormone. Only cells having appropriate receptor proteins will be able to respond to a given hormone.

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6
Q

(fuck this card)Different types of hormones

A

o Peptide hormones- insulin, glucagon.
o Catecholamines- epinephrine, norepinephrine, dopamine
o Indoleamines- melatonin
o Steroids- estrogen, testosterone, aldosterone
o Eicosanoids- prostaglandins

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7
Q

What concentration of hormones are necessary for them to do their job? How is it so different from neurotransmitter concentration?

A

Most hormones are effective at extremely low concentrations (10^-8 to 10^-12 molar within the ISF is effective.) In comparison, most NTs are present w/in the synaptic cleft at concentrations of approximately 10^-4 molar

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8
Q

What are pharmacological concentrations?

A

Pharmacological concentrations are hormone concentrations that can only be achieved by taking exogenous hormones.

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9
Q

What are some unintended effects of taking exogenous hormones like anabolic steroids?

A

Taking anabolic steroids- exogenous testosterone used by body builders, Aromatase enzyme converts testosterone into estrogen, resulting estrogen causes Gynecomastia.

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10
Q

Why is the pituitary gland called the “master gland” of the body?

A

Because it controls many other endocrine organs

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11
Q

Infundibulum

A

the pituitary gland is suspended from the hypothalamus by a stalk

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12
Q

Sella turcica

A

where the pituitary gland hangs out

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13
Q

Hypophysis

A

the pituitary

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14
Q

Adenohypophysis

A

anterior pituitary

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15
Q

Neurohypophysis

A

posterior pituitary

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16
Q

The anterior and posterior pituitary gland have different names and look different. This is due to how they are created during early development. How does each part form?

A

The post. Pituitary is an extention of neural tissue from the hypothalamus.

The ant. Pituitary is a true endocrine gland of epithelial origin- formed from the roof of the embryonic mouth

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17
Q

What is a neurohemal organ? Are they important?

A

How a neurohormone (a hormone secreted by a neuron cell) gets into the blood stream. Goes through a fenestrated capillary at a neurohemal organ. And they are important.

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18
Q

There are two areas of the hypothalamus that house the cell bodies of neurosecretory neurons whose axons terminals form the posterior pituitary gland. Do you remember the names of these two nuclei?

A

Supraoptic and paraventricular

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19
Q

What is a pituicyte?

A

Glial cells that (along with the axon terminals of neuroendocrine cells) form the post. Pituitary

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20
Q

What are the two different hormones produced by the neurons in the posterior pituitary?

A

Oxytocin and Antidiuretic Hormone (ADH) aka arginine vasopressin (AVP)

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21
Q

What does oxytocin do?

A

triggers maternal uterine contractions during childbirth
 Triggers milk ejection from breast during suckling
 May affect some male paternal behaviors
 Secretion of oxytocin is stimulated by dilation of cervix, stimulation of nipples, or the sound of a hungry baby crying.

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22
Q

What does the antidiuretic hormone (ADH) do?

A

 Increases water reabsorption by the kidneys
 Causes vasoconstriction of arterioles

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23
Q

Tropic vs non-tropic hormones

A

o Tropic- other endocrine glands as the target
o Non-tropic- hormones directly stimulate target cells

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24
Q

The anterior pituitary has endocrine cells that secrete a number of different hormones. Do you remember what they are? (there is a mnemonic device)

A

o FLAT PiG ME
 Follicle-stiumlating hormone (FSH)
* Testes/ovaries
 Lutenizing Hormone (LH)
* testes/ovaries
 Adrenocorticotropic hormone (ACTH)
* Adrenal cortex
 Thyroid-stimulating hormone (TSH)
* thyroid
 Prolactin
* Mammary glands
 Ignore I
 Growth hormone (GH)
* Liver, bones, other tissues
 Melanocyte-stimulating hormone (MSH) (from pro-opiomelanocortin)
* melanocytes
 Endorphin (from pro-opiomelanocortin)

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25
What does a gonadotrophs secrete?
secrete FSH and LH (follicle-stimulating and luteinizing)
26
What does a corticotrophs secrete?
secrete ACTH, MSH, and Endorphins (adrenocorticotropic, melanocyte-stimulating)
27
What does the term hypophysiotropic mean? These are hormones secreted by neurosecretory neurons in the hypothalamus. What do they do?
hormones that are secreted by neurosecretory neurons w/in the hypothalamus (pituitary regulating). Either stimulate (releasing hormones) or inhibit (inhibiting hormones) the secretion of hormones from the ant. Pituitary endocrine cells.
28
* What is the portal vessel system and what is the advantage of it?
o Hypothalamic-Hypophyseal Portal Vessel System- vascular link between hypothalamus and ant. Pituitary gland.  Neurohemal organ w/in the median eminence picks up tropic hormones secreted by hypothalamic neurons  A Portal System carries these hypophysiotropic hormones to the Ant. Pituitary  A capillary bed w/in the Ant. Pituitary allows its secreted hormones to enter the systemic circulation o Important functional advantages of a portal system: NO dilution of hormone, NO enzymatic destruction of hormone by the liver or lungs.
29
Negative feedback loops with the thyroid
o The hypothalamus secretes TRH (thyrotropic-releasing hormone) o TRH triggers section of TSH (thyroid stimulating hormone) from the ant. Pituitary o TSH triggers secretion of Thyroxin from the thyroid gland o Thyroxin inhibits the responsiveness of the ant. Pituitary to TRH, and inhibits secretion of TRH by the hypothalamus.
30
* The pericardium encloses the heart and has different layers. Do you know what they are and what they do? Where would you find fluid?
o Fibrous pericardium o Serous pericardium  Parietal layer- lines fibrous pericardium  Fluid in between these two guys  Visceral layer (epicardium)- covers heart surface
31
differences between the right and left side of the heart. Which ventricle is thicker? Why?
Left is thicker bc has to pump to the whole body compared to right that just has to pump for pulmonary circuit.
32
What are valves in the heart and what do they do?
o 4 valves in the heart that prevent backflow during pumping  Lub- tricuspid and mitral valves closing  Dub- aortic and pulmonary valves closing
33
what are some of the other functions of the heart?
o Delivers molecular oxygen and nutrients to tissues o Removes CO2 and wastes from tissues o Distributes metabolic heat and hormones in the blood o Secretes the hormone Atrial Natriuretic peptide (ANP) o Transports cells of immune system throughout the body.
34
Think about what blood is entering each side (where does deoxygenated blood enter, what about blood that has traveled to the lungs?) and the movement.
Deoxygenated blood from the body enters your heart on the right through the superior and inferior vena cava. It is then pumped to your right ventricle which then pumps the blood to your lungs.
35
What is the pulmonary circuit?
Pulmonary circuit o Right side of the heart o Carries oxygen poor blood to lungs for gas exchange and back to the heart.
36
What is the systemic circuit?
Systemic circuit o Left side of the heart o Fully oxygenated blood from lungs is then send out to all tissues of the body and returns it to the heart.
37
What are the layers of wall of the ventricle
epicardium, myocardium, endocardium
38
Epicardium
(epi= upon) o Thin, external epithelium, the outermost layer of the heart. o This is the visceral layer of the serous pericardium o Slides without friction against the parietal layer of the serous pericardium.
39
Myocardium
(myo= muscle) o Thick, middle layer o Cardiac muscle, the bulk of the heart. o Contractile muscle cells (cardiac myocytes)
40
Endocardium
(Endo= within; inside) o Thin epithelial (endothelial) & innermost layer. o Contracts blood in the chambers of the heart, but blood supply to the heart is through the coronary arteries.
41
Where does the blood supply to the heart come from? Do cells that contact the blood in the chambers of the heart get nutrients and etc from that blood?
Endocardium contracts blood in the chambers of the heart, but blood supply to the heart is through the coronary arteries. No they get the nutrients from somewhere else.
42
What are the two different kinds of heart cells?
contractile cells, pacemaker cells
43
The majority of cells in the heart are what kind?
Contractile cells compose 99% of heart cells. Pacemaker cells compose only 1%
44
What does it mean when a cell is considered autorhythmic? Where would you find these cells?
Autorhythmic= spontaneously fire APs. You find these in pacemaker cells.
45
How are action potentials propagated within the heart? Are neurons involved?
Pacemaker cells trigger cardiac action potentials. Neurons are not directly involved in this process.
46
The heart has some muscle cells that have endocrine function. What do they secrete? What does it do for blood pressure?
Some atrial muscle cells secrete a hormone called ANP= Atrial Natriuretic peptide. Lowers blood pressure.
47
Why are some cells considered restless?
Because they are constantly active (if your heart stops beating you’ll die)
48
Do you understand what a pacemaker potential is?
Spontaneous, rhythmically-occurring depolarizations that trigger action potentials in cells that are electrically connected to the pacemaker cell.
49
Do you know the three ion channels that are involved? (in pacemaker potential)
Voltage gated Ca2+ channels, HCN channels, K+ channels.
50
What is an HCN channel?
Hyperpolarization and cyclic nucelotide gated channel.
51
When someone has sinus rhythm which pacemaking node is the dominant pacemaking region of the heart?
When the SA node is establishing the heart rate.
52
What is an ectopic pacemaker?
When a region other than the SA node is abnormally establishing the heart rate. Results in abnormal heart contractions.
53
What is the interatrial pathway and the internodal pathway?
1) The Interatrial Pathway propagates APs from the SA Node into the atria walls. 2) The Internodal Pathway propagates APs from the SA Node into the AV Node.
54
Something happens between the SA node and AV node when action potentials are being propagated. Why must this occur?
There’s a delay of ~100 milliseconds at the AV node. This delay allows the ventricles to completely fill with blood before they contract.
55
What is the fibrous skeleton of the heart?
A dense connective tissue framework in the heart.
56
Why would an acellular region that electrically isolates the atria from the ventricles be needed?
To ensure the atria can fully contract and empty their blood into the ventricles before the ventricles before the ventricles begin to contract themselves.
57
What role do gap junctions play in the heart?
Gap junctions allow APs and small molecules to pass rapidly and directly between adjacent cardiac myocytes.
58
Intercalated discs are interesting connections between cardiac myocytes. What cell junctions are found in the intercalated discs?
Fascia adherens, desmosomes, gap junctions.
59
Fascia adherens are described as velcro between cells and desmosomes are considered spot welds. What is happening in these connections between cells and why would these be useful for cells in the heart?
cells and why would these be useful for cells in the heart? They are anchoring sites for actin and connect to the closest sarcomere.
60
Cardiac action potentials look a little different from what we’ve discussed before with skeletal muscles. What is the big difference (what is the plateau?)
Cardiac APs are long lasting because this causes the ventricles to remain contracted long enough to eject all the blood from the ventricles. Each ventricular myocyte must remain contracted long enough for the ventricles to completely eject all their blood into the pulmonary arteries and the aorta. Voltages gate Ca2+ generate the plateau.
61
What triggers contraction of heart muscle?
An electrical signal.
62
What is the point of having longer lasting action potentials in ventricles?
Because this causes the ventricles to remain contracted long enough to eject all the blood from the ventricles.
63
What ion channels are playing a role in cardiac action potentials?
Voltage-gated Na+ channels, Voltage gated Ca2+ channels, voltage gated K+ channels.
64
Do you understand cardiac type excitation-coupling?
Excitation-contraction (E-C) coupling is the process by which an action potential propagating along the sarcolemma triggers contraction of the myocyte.
65
There are a lot of similarities between what is seen in skeletal muscle e-c coupling and cardiac type, but there are differences. Know where you would find Cav1.1 vs. Cav1.2 or RyR1 vs. RyR2
Cav1.2 is found in cardiac muscle. RyR1 is located in skeletal muscle while RyR2 is found in cardiac muscle.
66
The heart is innervated, but is it required to function?
Not required to function
67
Talking specifically of the SA node, how do the sympathetic and parasympathetic neurons modify heart rate?
Sympathetic: secretes a neurotransmitter (norepinephrine) which increases heart rate Parasympathetic: secretes a neurotransmitter (acetycholine) which decreases heart rate.
68
What is tonic secretion?
Continuous release of ACh onto the SA node when the parasympathetic vagus nerves are cut.
69
What happens when the parasympathetic vagus nerves are cut and no longer innervate the SA node?
If both vagus nerves are cut the heart will have no innervation by parasympathetic motor neurons and the SA node will generate APs at a rate of ~100 Aps/min
70
What is a positive inotropic effect?
A positive inotropic effect increases contractility. A negative inotropic effect decreases contractility.
71
What is a negative chronotropic effect?
A positive chronotropic effect increases heart rate. A negative chronotropic effect decreases heart rate.
72
What happens when someone ingests digitalis?
Decreased heart rate.
73
The respiratory system does more than just move air in and out of the body. What are its other functions?
Communication, olfaction, acid base balance, gas exchange. Eliminates heat. Enhances return of venous blood to the heart, site of enzymatic modification of hormones, site of water loss.
74
External respiration has 4 parts to it. What are they
1. Ventilation 2. Gas exchange #1 3. Gas Transport 4. Gas Exchange #2
75
Internal respiration has how many parts to it?
One part. Cellular respiration is the metabolic consumption of molecular oxygen O2 within mitochondria inside your cells.
76
What structures play a role in the respiratory system?
Nose, pharynx, larynx, tracea, bronchi, lungs.
77
What are the conducting airways? Does the conducting zone participate in gas exchange?
Conducting airways: larynx, trachea, no (i think this is right but I'm not sure)
78
What is the respiratory zone? How does it differ from the conducting zone?
Gas exchange occurs in the respiratory zone, no gas exchange occurs in the conducting zone.
79
Where does gas exchange occur?
Respiratory zone of the bronchial tree.
80
What are alveoli and are they close to any capillaries?
Tiny air sacs at the end of the bronchioles. They are surrounded by capillaries.
81
What is the surface area of the lungs? How does that compare to something like the skin?
70-80 square meters. Lungs have about 30x more surface area than the skin (couldn’t find this in the powerpoint.)
82
What is Fick’s Law of diffusion?
The rate of diffusion is inversely proportional to the distance over which diffusion must occur.
83
What cell types are present in alveoli?
Type I alveolar cell a. Very thin walls facilitate gas exchange by diffusion Type II alveolar cells b. Secretes surfactant Macrophages (mobile white blood cells= WBCs) c. Phagocytize bacteria and other debris. They also secrete the enzyme trypsin which kills pathogenic gram-negative bacteria.
84
The liquid called surfactant is found on the inner surfaces of the alveoli. What does it do?
Reduces surface tension in the walls of the alveoli. Facilitates lung expansion. Reduces the work of ventilation.
85
What is neonatal respiratory distress syndrome?
The lungs of premature babies are not yet able to produce enough surfactant. This increases the effort needed to expand the lungs during ventilation, resulting in exhaustion of the baby.
86
What is the Mucociliary Apparatus (aka mucus elevator)? What does it do?
1. Motile cilia cover the inner surfaces of the lungs 2. Cilia beat in unison, moving a layer of mucus towards the mouth. 3. INhaled dust and pathogens become trapped in the mucus layer. 4. The mucus elevator cleans your lungs and prevents infection. 5. Air pollution paralyzes cilia, stopping the elevator and the cleaning process.
87
Why do the lungs remain inflated? What is the pleural cavity?
The lungs remain inflated because the pressure exerted by air within the alveoli exceeds the pressure within the pleural cavity. The pleural cavity is a potential space between the visceral pleura and the parietal pleura.
88
What does pneumothorax mean? What is atelectasis and how can it happen?
Pneumothorax means “air in chest”. Atelectasis means “collapsed lung” can happen from compressive (pressure on the lung), obstructive (blocakge in the lung), or contraction (scarring)
89
The food we eat must be digested. Why is that so important?
Salivary glands, stomach, pancreas, and small intestine.
90
What are some examples of mechanical digestion?
Cutting and grinding action of the teeth, churning action of stomach and small intestines, exposes more food surface to digestive enzymes.
91
Is there anything we need that can be absorbed directly from the food we eat?
Vitamins, amino acids, minerals, cholesterol, water
92
What are the five stages of digestion?
1. Ingestion (selective intake of food) 2. Digestion (mechanical and chemical breakdown of food into a form usable by the body.) 3. Absorption (uptake of nutrient molecules into the epithelial cells of the digestive tract and then into the blood and lymph.) 4. Compaction (Absorbing water and consolidating the indigestible redisude into feces.) 5. Defecation (elimination of feces)
93
What makes up the digestive tract? Is the pancreas part of it? What are accessory organs and can you name some examples?
The main digestive tract is: mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus. Accessory organs include: teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
94
Everywhere along the digestive tract has the same structural plan with four distinct layers. What are these layers? Which layer differs the most between different sections?
Mucosa (epithelial lining, layer that differs most between GI organs.) Submucosa (connective tissue that contains blood vessels, lymphatic vessels, and nerves) Muscularis (smooth muscle arranged in both circular and longitudinal directions) Serosa (loose connective tissue srrounded by squamous epithelium)
95
What makes up saliva? Do you know what the different components do?
Saliva is a hypotonic solution of 97% to 99.5% water and the following solutes: Salivary Amylase: hydrolysis of starch Lungual Lipase: breakdown of lipids Mucus: lubricates food Lysozyme: antibacterial.
96
What is a bolus?
Mass swallowed as a result of saliva binding food particles into a soft, slippery, easily swallowed mass.
97
What happens when we swallow?
1. Oral Phase: voluntary actions move the bolus to the back of the mouth. 2. Pharyngeal Phase: mechanoreceptors in the pharynx sense pressure which stimulates medulla oblongata to initiate swallowing reflex. 3. Esophageal Phase: peristalsis toward stomach and opening of upper and lower esophageal sphincters.
98
Once food reaches the stomach what happens?
Mechanical digestion: churning of food to increase surface area with gastric juices Chemical Digestion: Low pH about 1.5-3.5 due to HCI secretion. Denatures proteins, eliminates pathogens. Pepsin cleaves peptide bonds to reduce molecular weight of peptides: responsible for about 20% protein digestion.
99
Is there only chemical digestion?
not only chemical digestion
100
How did we learn about chemical digestion? Alexis St. Martin and Dr. Beaumont had a role to play. Do you know what happened to Alexis St. Martin?
We learned about it from Dr. Beaumont and Alexis St. Martin. Alexis had a fistula in his stomach that wouldn’t heal. Dr. Beaumont experiments often involved tying a string around pieces of food and inserting them in Alexis’s stomach.
101
What do parietal cells and chief cells do in the stomach?
HCI secretion, stimulated direction by vagus nerve, stimulated hormonally by gastrin and histamine.
102
Stomach secretions only need to happen when food is present (or about to be present). What is the cephalic phase and the gastric phase of stomach secretions?
Sight, smell, taste, or even thoughts of food signal stomach to begin gastric secretions. Signals processed by CNS and transmitted to stomach via the vagus nerve.

physiology. (8 decks)

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