Bài giảng điều hòa thân nhiệt ths nguyễn thị hòa châu

Figure 73-1 Estimated range of body “core” temperature in normal people.. QUA TRINH THAI NHIET ° Thải nhiệt bằng cách truyền nhiệt: v Truyền nhiệt bức xa.. {Truyền nhiệt trực tiếp.. v

DIEU HOA

THAN NHIET ThS Nguyễn Thị Hoài Châu

Oral °F °C Rectal

104-|- 40

a Hard exercise

102-| 39

Hard work, emotion WL 38 moderate exercise

A few normal adults 100- A few normal adults

Many active children : ~ Many active children

Usual range | 'lÏF37 | Usual range

of normal) 98-)_ - of normal

` —IÌ— 36

Early moming | 96- : Early morning

Cold weather, etc * ' Cold weather, etc

Figure 73-1

Estimated range of body “core” temperature in normal people

(Redrawn from DuBois EF: Fever Springfield, IL: Charles C Thomas, 1948.)

Epidermis<

Capillaries

Veins

Subcutaneous tissue Venous plexus

Arteriovenous anastomosis

QUÁ TRÌNH SINH NHIỆT

-Chuyền hóa cơ sở

° Vác động động lực đặc hiệu của thức ăn

Su co co

Kích thích tô.

QUA TRINH THAI NHIET

° Thải nhiệt bằng cách truyền nhiệt:

v Truyền nhiệt bức xa

{Truyền nhiệt trực tiếp

v Truyền nhiệt đổi lưu

° Thái nhiệt băng sự bôc hơi nước:

Walls Evaporation (22%)

Radiation (60%)

heat waves

~<

Conduction to air (1 ” :

Air currents Z7

objects (3%)

Mechanisms of heat loss from the body.

PHAN XA DIEU NHIET

CO CHE CHONG NONG

¢Gian mach mau da

-D6 mo hoi

¢Giam tao nhiet:

¥ Biéng an

¥ Biéng lam.

Vasodilated _,

Vasoconstricted

50 60 70 80 90 100 110 12

Environmental temperature (°F)

Figure 73-3

Effect of changes in the environmental temperature on heat con-

ductance from the body core to the skin surface (Modified from Benzinger TH: Heat and Temperature Fundamentals of Medical Physiology New York: Dowden, Hutchinson & Ross, 1980.)

Deamon

Aprons

ae Re *

M8

E

—

oO

g

œ

Ww

Ỳ

VÀNG

VN sào k Tat

NGHIÊN

Nà

2

oO

a

vy

Sympathetic nerve

petal oe 22/711: nợ

Sweat gland innervated by an acetylcholine-secreting sympa-

thetic nerve A primary protein-free secretion is formed by the glandular portion, but most of the electrolytes are reabsorbed in the duct, leaving a dilute, watery secretion

Xu

we

PHAN XA DIEU NHIET

CO CHE CHONG LẠNH

°Co mạch da, dựng lông

° [lăng tạo nhiệt

v Run

v Kích thích giao cảm làm tăng tiết Epiniphrine

va Norepiniphrine

¥ Tang tiét Thyroxin.

f0

Atmospheric temperature (°F)

Figure 73-6

Effect of high and low atmospheric temperatures of several hours’

duration on the internal body “core” temperature Note that the

internal body temperature remains stable despite wide changes

in atmospheric temperature

90

——— Heat production

80 ¬ ==== Lvaporative heat loss

70 ¬

60 ¬

90 ¬

40 3

30 ¬

20 ¬

10 ¬

36.4 366 368 370 37.2 3/4 37.6

Head temperature (°C)

Figure 73-7

Effect of hypothalamic temperature on evaporative heat loss from the body and on heat production caused primarily by muscle activity and shivering This figure demonstrates the extremely crit-

ical temperature level at which increased heat loss begins and

heat production reaches a minimum stable level

90 ¬

33°C

60 ¬

Skin temperature

Sweating 32°C

40-

a4

305

30°C

0=

: Set-point 29°C

10-4 Insensible

evaporation

36.0 36.2 36.4 36.6 36.8 37.0 37.2 37.4

Internal head temperature (°C)

Figure 73-8

Effect of changes in the internal head temperature on the rate of evaporative heat loss from the body Note that the skin tempera- ture determines the set-point level at which sweating begins (Courtesy Dr T H Benzinger.)

Skin temperature (20°)

90 = †

80 3

7Ù"

Shivering

a

60 ¬

Set-point

Basal heat

production

10 5

36.6 36.8 37.0 37.2 37.4 37.6

Internal head temperature (°C)

Figure 73-9

Effect of changes in the internal head temperature on the rate of

heat production by the body Note that the skin temperature

determines the set-point level at which shivering begins (Courtesy Dr T H Benzinger.)

Temperature regulation seriously impaired Temperature regulation efficient in febrile disease,

health, and work

Temperature regulation impaired

Temperature regulation

lost

Figure 73-10

4

<

-lIÏF

110- pa

(4064/54 — =40 102¬ÍF

_— L 38

v8 [H36

94/7 “I-34

90-||- 32

86-|- 30

82-|-28

74124

Upper limit

of survival?

Heatstroke Brain lesions

Fever therapy

Febrile disease and hard exercise

Usual range

of normal

Lower limit

of survival?

Body temperatures under different conditions (Redrawn from:

DuBois EF: Fever Springfield, IL: Charles C Thomas, 1948.)

Set-point

105 - suddenly | === Setting of the thermostat

raisedto | Actual body temperature

œ104 5 high value

Crisis

= “1023 ! | i Vasodilation

E1014 | Chills: Set-point

99 5 secretion i

98 4 Shivering :

Time in hours

Figure 73-11

Effects of changing the set-point of the hypothalamic temperature

controller.