Endocrine regulation of physiological function Flashcards
1
Q
Hormones fall into
three major classes:
A
Polypeptides, steroids,
and amines
2
Q
which hormones are water soluble?
A
Polypeptides and most
amines are water soluble(This makes the steroid hormones fat soluble)
3
Q
what is the difference between water soluble and fat soluble hormones?
A
Water-soluble hormones
are secreted by
exocytosis, travel freely in
the bloodstream, and
bind to cell-surface
receptors
Lipid-soluble hormones
diffuse across cell
membranes, travel in the
bloodstream bound to
transport proteins, and
diffuse through the
membrane of target cells
They bind to receptors in
the cytoplasm or nucleus
of the target cells
4
Q
why do you need glucose in stress?- what hormone increases glucose availability?
A
glucose required for energy: pathways in cell stimulated by adrenaline to increase
glucose availability
5
Q
give an example of an endocrine gland?
A
such as the thyroid and
parathyroid glands and testes or
ovaries- they are ductless
6
Q
give the exocrine glands example
A
salivary glands, have ducts to carry
secreted substances onto body
surfaces or into body cavities
7
Q
give examples of organs that also have hormone secretion too.
A
While the heart, kidneys, and other organs have their primary roles, they also produce hormones, making them part of the endocrine system
8
Q
positive feedback- Simple neuroendocrine pathway
A
suckling stimulus, hypothomes to pituitary oxytocin- to Smooth muscle in
mammary glands
Milk release
9
Q
negative feedback- Simple endocrine pathway
A
endocrine cell, Low pH in
duodenum, S cells of duodenum, Secretin Pancreatic cells
RESPONSE Bicarbonate release
10
Q
what coordinates endocrine signalling
A
The hypothalamus coordinates endocrine signalling
11
Q
what is the pituitary gland made up of
A
composed of the posterior pituitary
and anterior pituitary
12
Q
Posterior pituitary does what?
A
stores and secretes
hormones that are made in the hypothalamus
13
Q
what is the other name for the posttrial pituitary
A
Neural link (PP also known as
neurohypophysis)
14
Q
Anterior pituitary does what and what is it also called?
A
makes
and releases hormones
under regulation of the
hypothalamus
Vascular link (AP also known
as adenohypophysis)
15
Q
ADH target organ
A
The kidneys tubules
16
Q
Oxytocin
A
Mammary glands,
uterine muscles
17
Q
what does alcohol do?
A
Alcohol inhibits secretion of ADH = increased volume of dilute urine
18
Q
Anterior pituitary stimulates a lot more hormones name a few name some with Tropic effects only
A
FSH and LH, TSH and ACTH(TO ADRENAL CORTEX)
19
Q
Nontropic effects only
A
Prolacin and MSH( Melanocytes)
20
Q
Tropic and
nontropic effects
A
GH, Liver, bones,
other tissues
21
Q
what is a tropic hormone
A
causes secretion of another hormone
22
Q
the tropic effects of tyroid, THS
A
If thyroid hormone levels drop in the blood:
The hypothalamus secretes thyrotropin-releasing hormone (TRH).
TRH signals the anterior pituitary to release thyroid-stimulating hormone (TSH).
TSH stimulates the thyroid gland to release more thyroid hormone.
23
Q
This causes the thyroid to enlarge, resulting in
a goiter how does this happen?
A
Iodine is needed to produce thyroid hormones.
When there isn’t enough iodine in the diet, the thyroid can’t make enough thyroid hormone, so it compensates by growing larger to try and produce more.
24
Q
what is TRS
A
Neurosecretory cells secrete TRH (Thyrotropin-Releasing Hormone) into the blood.
The blood carries TRH to the anterior pituitary.
TRH stimulates the anterior pituitary to release TSH (Thyroid-Stimulating Hormone), also called thyrotropin.
25
where are the adrenal glands located?
located on top of the kidneys
26
can you explain what the adrenal glands look like?
Each adrenal gland consists of two glands: adrenal medulla (inner) and adrenal cortex (outer)
27
The adrenal medulla
Adrenal medulla secretes adrenaline and noradrenaline (fight, flight or freeze)
28
Adrenal cortex
secretes corticosteroids – glucocorticoids and mineralocorticoids
28
what are the Glucocorticoids ie give an example
e.g., cortisol-, influence glucose metabolism and the immune system
29
Mineralocorticoids
eg aldosterone, affect salt and water balance ( think minearals for example salt )
30
adrenaline has multiple effects what are they?
Blood glucose level
increases.,
Blood vessel dilates,
increasing flow to
skeletal muscle.,
Blood vessel constricts,
decreasing flow to
intestines.
31
what do the testis often produce?
primarily synthesize androgens, mainly
testosterone,
32
what hormone is mainly responsible for female development?
Oestrogens, most importantly oestradiol, are
responsible for maintenance of the female reproductive
system
33
what is involved in pregnancy development- maintains the uterus
progesterone is primarily involved in
preparing and maintaining the uterus for pregnancy
34
for the synthesis of sex hormones is controlled by what?
gonadotropins and follicle-stimulating hormone and
luteinizing hormone
35
where are the follicle-stimulating hormone and
luteinizing hormone form?
anterior pituitary
36
Gonadotropin secretion is controlled by gonadotropin releasing hormone from the........
hypothalamus
37
what is an endocrine disorder?
Endocrine disease results when a gland produces too much (excess) or
too little (deficiency) of an endocrine hormone, called a hormone
imbalance- This can be due to the development of lesions (such as nodules or
tumours) in the endocrine system, which may or may not affect
hormone levels
38
the pancreas endocrine beta cells produce what?
b(beta) cells
Site of insulin synthesis and
secretion
39
the alpha cells of the pancreas produce what?
glucagon
40
insulin is considered what type of hormone and why ?
Anabolic hormone- Promotes cellular uptake of glucose, fatty
acids, and amino acids and enhances their
conversion into glycogen, triglycerides,
and proteins, respectively
41
when is insulin secreted?
Primary stimulus for secretion is
increase in blood glucose
concentration
42
one major sign of diabetes?
Urine acquires sweetness from excess
blood glucose that spills into urine
43
type 1 diabetes?
Characterized by lack of insulin
secretion (autoimmune destruction
of b cells)
44
type 2 diabetes
Characterized by normal or even
increased insulin secretion but
reduced sensitivity of insulin’s target
cells
45
the flow of the fluids into the compartments of the body
External Environment → Plasma (Blood) → Interstitial Fluid → Cytosol (Inside Cell)
46
what is the cardiac cycle?
The heart contracts and relaxes in a rhythmic cycle called the
47
Contraction:
systole
48
Relaxation:
diastole
49
The flow form the heart is what type of direction?
unidirectional
50
Cardiac output- what is the calculation.
Heart rate (beats/min) x stroke volume (mls/beat)
Exercise does what to this: Exercise: increases several fold.
51
elite athletes would have what at rest?
low heart rate and high
stroke volume - high stroke volume to pump loads of blood- low heart rate- as it is so efficient
52
can you relate the heart to the nervous system?
Parasympathic:
Innervates SA node
Slows heart rate
Sympatheic:
Innervates SA node
Increases heart rate-
Exercise: decreased parasympathetic activity & increased sympathetic activity
53
what is the signal passing like?
Signals (yellow)
from SA node
spread through
atria.
Signals are
delayed at AV
node.
54
p wave
atrial depolarisaion
55
QRS complex
ventricular depolarisaion
56
T wave:
ventricular repolarisation
57
Abnormal Heart Rates for example, Tachycardia-
fast
58
Bradycardia
slow
59
Fibrillation
Loss of coordination of electrical activity. Can be corrected
by defibrillation
60
what is the blood veins relationaship?
Ventricle - artery - arteriole - capillary - venule - vein - atrium. VAACVVA- Intuitive as artery- arteriole
61
what is inside every vein and artery?
endothelium
62
in accordance to a vein what is the basal laminin ?
The basal lamina is a thin layer of extracellular matrix (a sheet-like structure) that lies beneath the endothelial cells in the wall of a vein.
63
what is the core concept of haemodynamic?
Fluids (eg. air, blood) move
from regions of higher
pressure to lower pressure
down a pressure gradient
64
put in order of highest to lowest pressure.
Aorta (highest pressure — blood just pumped out of left ventricle)
Arteries
Arterioles
Capillaries
Venules
Veins
Venae Cavae (lowest pressure — returning blood to the heart)
65
breathing follows bolyles law- but what does this mean?
At constant temp, pressure and volume are inversely related
66
inhalation
Diaphragm contracts (moves down).
Lung volume increases, pressure would decrease ( ie this happens when lung gets larger )
67
exhalation
EXHALATION: Diaphragm relaxes (moves up).
Lung volume decreases: Pressure in lung
increases above atmospheric P
68
Spirometry is what-
Pulmonary function test
69
what is the general composition of air
79% Nitrogen
21% Oxygen
Trace amounts carbon dioxide, helium,
argon, etc
70
Each haemoglobin protein can bind how many oxygen
molecules
4
71
how much carbon dioxide acc enters the blood?
Only about 7% of CO2 from respiring cells
diffuses into the blood and is transported in
blood plasma, bound to hemoglobin
72
what happens when plasma is infected with Co2
The remainder diffuses into erythrocytes and
reacts with water to form H2CO3, which
dissociates into H+ and bicarbonate ions (HCO3
–)
Reac1on catalyzed by carbonic anhydrase
73
what is the Bohr shift?
CO2 produced during cellular respiration lowers blood pH and decreases the affinity of
hemoglobin for O2
74
where is the breathing centre of the brain?
medulla oblongata of the brain
75
how does the medulla know to regulate the depth of breathing?
Medulla regulates the rate and depth of breathing in response to pH changes in the cerebrospinal fluid
(influence of CO2) weird i know but cerebrospinal fulid is also in spine and brian.
76
what is normal oxygen consumption at rest?
Normal oxygen consump1on at rest approximately
250ml/min- females 20% less.
77
Physiology Research Focus: hypoxia
insufficient oxygen in in body- surroundings.- High altitude to a physiologist starts around 1500m
(5000ft), the altitude where the body senses
changes in the oxygen level
78
Precapillary sphincters
small muscles- located in junctions- act as valves.
79
Thoroughfare
channel
direct pathway between arteriole and capillaries
80
lymph vessels
Blind ending capillaries
Large vessels empty into subclavian vein
81
what is the main function of lymph vessels?
Major functions
Tissue drainage
Return leaked plasma proteins
Absorption of digested fat
Defence (lymph nodes)
82
what is Oedema
swelling caused by excess fluid or institute fluid. Reason blockage or increased capillary pressure from kidney disease or lack of protein in blood.
83
how could an airplane flight cause oedema
Aeroplane flight (via decompression & immobility)- can cause Increased venous pressure
84
what does regulate plasma composition?
kidneys- urine is acc unfiltered plasma
85
urine system refinement?
Filtration: Filtering of plasma
Reabsorption: Reclaiming valuable
solutes
Secretion: Adding nonessential solutes
and wastes to the filtrate
Excretion: Processed filtrate containing
nitrogenous wastes is released from the
body
86
what is the vasa recta?
the specialised blood vessels in the kidney.
87
Bowman’s capsule
its filtrates contains salts, glucose, amino acids, vitamins,
nitrogenous wastes, and other small molecules
88
the proximal tubules
Reabsorption of ions, water, and nutrients takes place
Molecules transported actively and passively from the filtrate into the interstitial fluid and then
capillaries
As the filtrate passes through the proximal tubule, materials to be excreted become concentrated
Some toxic materials are actively secreted into the filtrate
89
Descending Limb of the Loop of Henle
Reabsorption of water continues through channels formed by aquaporin proteins-
90
Ascending Limb of the Loop of Henle
Salt but not water is able to diffuse from the tubule into the interstitial fluid
The filtrate becomes increasingly dilute
91
Distal Tubule
The distal tubule regulates the K+ and NaCl concentrations of body fluids
The controlled movement of ions (H+ and HCO3
–) contributes to pH regulation
92
Collecting Duct
Carries filtrate through the medulla to the renal pelvis
One of the most important tasks is reabsorption of solutes and water
Urine is hyperosmotic to body fluids
93
Antidiuretic hormone
is also called vasopressin
ADH molecules released from the posterior pituitary bind to and activate membrane
receptors on collecting duct cells
94
what regulates the concentrations of solutes in the blood?
Osmoreceptor cells are specialized neurons located in the hypothalamus
95
where does ADH work on
ADH acts on the kidneys, particularly the distal convoluted tubules and collecting ducts, increasing their permeability to water.
96
NORMAL
BLOOD OSMOLARITY
285–295 mOsm/L
97
what is blood pressure?
Blood pressure is a force exerted in all
directions, including against the walls of
blood vessels
98
what also helps regulate blood pressure?
The recoil of elastic arterial walls plays a role in
maintaining blood pressure
99
what dissipates high blood pressure
The resistance to blood flow in the narrow
diameters of tiny capillaries and especially
arterioles dissipates much of the pressure
100
what is systolic pressure?
is the pressure in the arteries
during ventricular systole; it is the highest
pressure in the arteries
101
Diastolic pressure
is the pressure in the arteries
during diastole; it is lower than systolic
pressure
102
flow
pressure gradient / resistance to flow
103
Poiseuille’s Law or resistance to flow
R=length x velocity / radius^4
104
Is a major inducer of vasodilation
Nitric oxide
105
Is a potent inducer of vasoconstriction
The peptide endothelin- produces by the epithelial cells
106
Vasoactivity influenced by
nerves, hormones and local effects in tissues
107
explain the role of Metabolism on vasoactivity-
decreased O2 causes dilation, heat causes dilation
108
Hormones explain hormones role of vasoacrivity
Histamine dilates,
ADH/Vasopressin constricts)
109
Total Peripheral Resistance
The summed resistance throughout the circulation
110
Blood pressure for a healthy young adult
human at rest should
<120 mm Hg at
systole and 70 mm Hg at diastole
111
MAP=
CO x TPR or HR x SV x TPR
112
what is TPR:
Total peripheral resistance:
113
vasoconstriction preformed by veins does what
Increases blood pressure
114
what are the types of Baroreceptors?
A fibres (myelinated)
Low pressure (30-90 mmHg)
Important at rest
C fibres (unmyelinated)
High pressure (70-140 mmHg)
Increasingly active at higher pressures
115
what are baroreceptors?
Specialised nerve endings that respond to stretch of vessel wall
Indirect response to changes in Blood pressure.
116
locations of baroreceptors?
Carotid sinus & aortic arch
117
what is a key feature of baroreceptors?
for short term regulation ,Eg in hypertension they reset within 1-2 days
118
when blood pressure rises or falls what happens- what does the barorespetrs do?
When blood pressure rises or falls, these baroreceptors send signals to a part of the brainstem called the NTS (Nucleus Tractus Solitarius), located in the medulla oblongata.
119
lets say we want a calming effect. What should you do?
The NTS sends signals to the nucleus ambiguus, which then sends vagus nerve signals to the heart.
This slows down the heart rate (HR) — a calming effect.
120
say we are stressed-
Hypothalamus & Amygdala
These areas process emotions and stress.
They can inhibit or override the baroreceptor reflex, allowing your blood pressure to rise temporarily as part of the fight-or-flight response.
121
Angiotensin II
raises blood pressure and
decreases blood flow to the kidneys
It also stimulates the release of the
hormone aldosterone, which
increases blood volume and pressure
122
why does hypertension occur?
peripheral flow resistance
123
Primary/essential hypertension
Mostly via aspects that affect arteriolar smooth muscle
Cumulative effect of genetic, lifestyle & environmental
factors
124
difference between hypertension and high blood pressure?
hight blood pressure is temporary- by stress, exercise, caffeine, pain, or anxiety
Hypertension- A chronic (long-term) medical condition where blood pressure is consistently high.
125
5% of cases, secondary
to disturbance of normal physiological function
e.g. renal diseases, adrenal disease
126
drug treatment of hypertention: Thiazide diuretics
Inhibit Na+/K+/Cl- exchange in distal renal tubule
127
b-blockers:
Reduce HR & contractility
128
a-blockers:
Reduce sympathetic tone; dilate arteriolar smooth muscle
129
L-type Ca2+ channel blockers
relaxation of vascular smooth muscle → reduced
resistance
130
ACE inhibitors:
Diuretic actions; Inhibit aldosterone formation
