Post on 20-Dec-2015
10-1
e. Pressure must be regulated to control flow
(1) Cardiovascular system (fast)
(a) cardiac output
increase c.o., increase pressure
(b) peripheral resistance
increase p.r., increase pressure
vasoconstriction of arterioles
compress veins by smooth or striated muscle contraction
10-2
(2) Osmoregulatory system (slow, kidney, liver)
pHy >> pOs:
fluid leaves blood, blood volume drops, pressure drops
pOs >> pHy:
fluid enters blood, blood volume increases, pressure increases
Retaining water or salt in blood will increase pressure
10-3
f. Mechanisms of Pressure Regulation
(1) Autonomic reflex arcs
(a) Baroreceptor Reflex
baroreceptors in aortic/carotid bodies in arteries
increased blood pressure causes increased a.p.s to medulla
activates PSNS, deactivates SNS
slows heart, increases vasodilation
10-4
(b) Chemoreceptor Reflex
chemoreceptors in circulation and CNS monitor pH, CO2, O2
information relayed to medulla to regulate SNS, PSNS
Medulla integrates sensory information
Generates output to ANS to control cardiac output and vascular smooth muscle activity
Direct flow to tissues with highest metabolic demand
10-5
(2) Local (intrinsic) control in vessels
Smooth muscle activity modified by local environment
Results of metabolic activity cause vasodilation
decreased blood O2
increased blood K+
increased temperature
Endothelium produces vasodilators: NO
Activity promotes blood flow to tissues:
Active Hyperemia
10-6
g. Regulate pressure to maintain homeostasis
(1) Response to postural changes in gravitational field
lie down: mean = 100 mm in all arteries
stand up: gravity causes pooling in lower limbs
Reaction: activation of SNS
peripheral vasoconstriction in lower extremities, both arterial and venous
10-7
Arterial mean pressure:
legs: 180 mm
heart: 100 mm
head: 62 mm
Forces flow from legs to above heart
But over time, still pooling in extremities
Force blood up by skeletal muscle contraction
10-8
(2) Exercise/stress
Must adjust flow to supply most active tissue
Activation of SNS
increase heart rate and strength (beta)
vasoconstriction of viscera (alpha)
vasodilation in muscle (beta, local)
redirection to drive flow to muscle
10-9
750Brain
Resting Human
10-10
200750
HeartBrain
Resting Human
10-11
1000
200750
HeartBrain
Muscle
Resting Human
10-12
1000
400
200750
HeartBrain
MuscleSkin
Resting Human
10-13
1000
950
400
200750
HeartBrain
MuscleSkin
Kidney
Resting Human
10-14
1200
1000
950
400
200750
HeartBrain
MuscleSkin
Kidney
Abdomen
Resting Human
10-15
500
1200
1000
950
400
200750
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Resting Human
10-16
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Resting Human
10-17
750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
10-18
700750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
10-19
12,600
700750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
10-20
12,600
1900
700750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
10-21
12,600
600
1900
700750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
10-22
600
12,600
600
1900
700750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
10-23350
12,600
600
1900
700750
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
600
10-24350
12,600
600
1900
700750
17,500
500
1200
1000
950
400
200750
5,000
HeartBrain
MuscleSkin
Kidney
Abdomen
Other
Strenuous Exercise
600
10-25
h. Increased blood pressure adaptive
(1) Increases flow therefore capillary filtration and exchange
(2) Increases nutrient, O2 supply, waste removal
10-26
VII. ENDOCRINE SYSTEM
A. Basics of Hormonal Communication
1. Chemical communication
All cells communicate via diffusable chemicals
10-27
2. Secretion: the controlled release of chemicals by a cell can occur in several ways
OUTSIDE
ECF
BLOOD
Duct
10-28
2. Secretion: the controlled release of chemicals by a cell can occur in several ways
Autocrine Paracrine
Exocrine
Endocrine
ACCESS TO ALL CELLS
10-29
Neurotransmitters are paracrine, require direct cellular contact with controlled target tissue
Endocrine system
chemical control without direct cellular contact
use circulatory system as delivery mechanism
endocrine communication slower, more general than nervous
10-30
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-31
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-32
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-33
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-34
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-35
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-36
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-37
3. Organs of system: Endocrine Glands
Specific secretory tissues producing hormones
4. Hormone: organic chemical agent
secreted into the circulation
by a specific living tissue (endocrine gland)
acting in minute amounts
at a distance from its source
to modify the activity of a distinct target
resulting in coordinated activation of target cells
10-38
5. Types of hormone molecules
a. Proteins and peptides
tripeptides to glycosylated proteins
protein synthesis, vesicle storage and release to capillaries by exocytosis
10-39
b. Lipids
steroids: built from cholesterol
prostaglandins: C20 fatty acids
enzymatic synthesis
type produced depends on enzymes active
lipid soluble, so can’t be stored in vesicles
immediate release by diffusion
10-40
c. Amino acid derivatives
enzymatic modification of amino acids
catecholamines, thyroid hormones, indoleamines
released from vesicles