Pituitary gland and it's hormones

Pituitary gland and it's hormones.

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Assignment of
physiology
Pituitary gland hormones in physiological
coordination

This topic contains the information about the pituitary gland
and the hormones which are secreted by different lobes of
pituitary gland and their roles in the physiological
coordination.

MALAIKA MUSKANRoll No. 875
SEMESTER. 5 submitted to: Dr. SAGEER
AHMED
11/14/2019

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PITUITARY GLAND: 4
 The pituitary gland is the pea-sized gland that is housed within a bony structure (sellaturcica) at 5
the base of brain. The sellaturcica protects the pituitary but allows very room for expansion. 6
 The pituitary gland controls the function of most other endocrine gland and is therefore 7
sometimes called master gland. 8
 In turn, the pituitary is controlled in large part by the hypothalamus, a region of brain that lies 9
just above the pituitary. 10
The pituitary has two distinct parts: 11
 Anterior lobe 12
 Posterior lobe 13
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 The lobes are connected to the hypothalamus by a stalk that contains blood vessels and nerve 15
cell projections (nerve fibers, or axon). 16
 The hypothalamus controls the anterior lobe by releasing hormones through the connecting 17
blood vessels .it control the posterior lobe through nerve impulse. 18
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PITUITARY AND THE TARGET TISSUES: 21
 The pituitary gland produces a different hormones affects a specific part of 22
body i-e, target organ or tissues. 23
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HORMONES TARGET ORGANS/
TISSUES
ADENOCORTICOTROPIC HORMONE (ACTH) ADRENAL GLAND
MSH SKIN
FOLLICLE STIMULATING HORMONES (FSH) OVARIES OR TESTES
GROWTH HORMONES MUSCLE AND BONE
LUTEINIZING HORMONES (LH) OVARIES OR TESTES
OXYTOCIN UTERUS AND MEMORY GLAND
PROLACTIN MAMMARY GLAND
THYROID STIMULATING HORMONES THYROID GLAND
VASOPRESSIN KIDNEYS
ENDORPHIN BRAIN AND IMMUNE SYSTEM
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28
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LOBES OF PITUITARY GLAND: 30
 ANTERIOR LOBE 31
 POSTEROR LOBE 32
 Median pituitary 33
 Each lobe produces and release different hormones. 34
 Detail below: 35
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Anterior lobe hormones: 38
 The anterior lobe produces and release six main hormones: 39
1) STH (SOMATOTROPIN) 40

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2) FSH ( FOLLICLE-STIMULATING HORMONE) 41
3) TSH (THYROID STIMULATING HORMONE) 42
4) ACTH ( ADRENOCORTICOTROPIC HORMONE) 43
5) PROLACTIN 44
6) LUTEINIZING HORMONE 45
Hormones and their function: 46
All the HORMONES of major pituitary, except for growth hormones , exert their principal effects mainly 47
by stimulating target glands, including thyroid gland, adrenal cortex, ovaries, testicles, and mammary 48
gland. The function of each of these pituitary hormones are so intimately concerned with the function of 49
respective target gland that, except for growth hormones, their function are described below; 50
1) Growth hormone: (SOMATOTROPIC) 51
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Growth hormones also called somatotropin or somatotropic hormone, is a small protein molecule that 53
contains 191 amino acids in a single chain and has a molecular weight of 22,005. 54
FUNCTION: 55
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1. Growth hormones which regulates the growth of bones and muscles. 57
2. It also regulates the physical development and has important effects on body shape by 58
stimulating muscle. 59
3. It has multiple specific metabolic effects like; enhances body protein, decrease fat store 60
and conserve carbohydrates. 61
4. Promote the protein deposition in tissues 62
5. It directly enhances the transport of amino acids through the cell membrane to interior 63
of cell. 64
6. Increased nuclear transcription of DNA to form RNA 65
7. It also decrease the catabolism of protein and amino acids. The probable reason for this 66
decrease is that GH also mobilize the large quantities of free fatty acids from the 67
adipose tissues and these are used to supply most of the energy for the body cells thus 68
acting as a “protein sparer”. 69
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2) TSH: (Thyroid stimulating hormones) 85
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Thyroid-stimulating hormone, which stimulates the thyroid gland to produces thyroid hormones. 87
Thyroid hormones are as follow; 88
1) Thyroxin 89
2) Triiodothyronine 90
FUNCTION: 91
1) Increase the transcription of large numbers of genes. 92
2) Thyroid hormones activate the nuclear receptors. 93
3) Increase the cellular metabolic activity; increase the number and activity of 94
mitochondria, increase the Active transport of ions through cell membrane. 95
4) These hormones also have effect on growth. 96
5) Effect on specific body function like; stimulation of fats and carbohydrates 97
metabolism ;increase the heart rate ,heart strength , respiration , gastrointestinal 98
motility, blood flow & cardiac output etc. 99
6) Effect on sexual functions. 100

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Thyroid and its working: 106

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107
3) ACTH: (adrenocorticotropic hormone) 108
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Adrenocorticotropic hormone also called corticotrophin, which stimulate the adrenal gland to produce 110
cortisol, corticosterone, aldosterone and other hormones. 111
 Adrenal gland has two sections; cortex and medulla. 112
 Both sections secrete different hormones and perform different functions: 113
The hormones of adrenal cortex are: 114
 Mineralocorticoid 115
 Glucocorticoid 116
 Testosterones 117
The hormones of adrenal medulla are: 118
 Epinephrine 119
 Nor-epinephrine 120
Functions: 121
1) Aldosterone increases renal tubular reabsorption of sodium and secretion of potassium. 122
2) Aldosterone stimulates sodium and potassium transport in sweat glands, salivary glands 123
and intestinal epithelial cells to conserve body salt in hot environment and the effect on 124
salivary gland is necessary to conserve salt when excessive saliva is lost. 125
3) Metabolic effect of Cortisol and glucocorticoid on metabolism is the ability to stimulate 126
gluconeogenesis by liver. 127
4) Cortisol increases the enzymes required to convert amino acids to glucose in liver cells. 128
5) Effects of cortisol on protein metabolism; reduction in the cellular protein. 129
6) Effect on cortisol on fat metabolism; metabolization of fatty acids. 130
7) Epinephrine eliminates the production of gastrin. 131
8) It facilitates the blood move towards the muscles. 132
9) Nor-epinephrine resists the blood to move towards stomach. 133
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137
ACTH and it’s working. 138
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4) PROLACTIN: 140
141
It produces from adenohypophysis by nature. It is polypeptide chain. The target cells are gonads. 142
Function. 143
1. Premigration restlessness in birds 144
2. Courtship dances 145

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3. Courtship sounds 146
4. Changes in external genitalia 147
i)Size of labia majora &minors (females) 148
ii) Size of penis 149
iii) Color changes 150
5. Onset of rut signs 151
6. Initiate and maintain lactation 152
7. Induce ductal growth of breast 153
8. Induce lobular-alveolar system 154
9. It takes part in synthesis of milk protein like casein and lactoalbumin 155
10. It is important in control of osmolality 156
11. It helps fetal lung development 157
12. Take part in formation steroids from adrenal cortex, testes and ovaries 158
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5) FSH: {Follicles-stimulating hormones} 164
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FSH is a gonadotropin, a glycoprotein polypeptide hormone.FSH is synthesized and secreted by the 166
gonadotropic cells of the anterior pituitary gland. 167

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Function: 168
1) In women, this hormone stimulates the growth of ovarian follicles in the ovary before the 169
release of an egg from one follicle at ovulation. 170
2) In men, it stimulates testicular growth and enhances the production of an androgen-binding 171
protein by the sertoli cells, which are a component of the testicular tubule necessary for 172
sustaining the maturing sperm cells. 173
3) Pubertal development 174
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6) Luteinizing hormone: 180
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LH is a hormone produced by gonadotropic cells in the anterior pituitary gland. 182
Function: 183
1. In females, an acute rise of LH triggers ovulation and development of the corpus luteum. 184
2. Promote the secretion of estrogen from the mature follicle 185
3. Release the ovum from the ovarian follicles 186
4. Corpus luteum produces progesterone and estradiol under the influence of LH. 187

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5. Produce the testosterone from the leydig cells off testes. 188
Posterior lobe hormones: 189
 The hormones of posterior lobe of pituitary gland are: 190
 Oxytocin 191
 Vasopressin 192
1) Vasopressin: 193
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Vasopressin is called so because of constriction of blood vessels. This is also known as anti-diuretic 195
hormone. 196
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Function: 198
The function of vasopressin is: 199
1. Regulate the tonicity of body 200
2. Reabsorb the solute-free water and return it to the circulation from tubules of nephron 201
3. Maintain osmolality (concentration of dissolved substances such as glucose, in the serum) 202
4. Maintain the volume of water in extracellular fluid 203
5. Increase blood volume, cardiac output and arterial pressure 204
6. Another function is vasoconstriction 205
7. It is used to manage the anti-diuretic hormone deficiency 206
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2) Oxytocin: 208
Oxytocin is also known as love hormone, is released by pituitary gland and is responsible for human 209
behavior associated with relationship and bonding. 210
Function: 211
1. It is mostly used to help mother produce the contractions in labor and control bleeding 212
2. It stimulates the uterine muscles to contract and also increase the production of prostaglandins, 213
which increase the contraction further 214

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3. Stimulates the milk ejection 215
4. It is found in men too and has effect on testosterone production and movement of sperm 216
5. It is also involved in sexual arousal and love bonding 217
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Median pituitary lobe: 220
Median pituitary lobe secretes the MSH (melanocytes-stimulating hormone). 221
Function: 222
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MSH stimulates the production and release of melanin ( a process referred to as melanogenesis) by 224
melanocytes in skin and hairs. Acting in hypothalamus, MSH suppresses the appetite. This also 225
contributes in sexual arousal. 226
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Exercise: 229
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Mcq’s 231
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1) The target organ/organs of Oxytocin is/are: 233
a) Uterus b) mammary glands c) testes d) a&b both 234
2) The anterior lobe of pituitary gland comprises the _______ weight of whole pituitary gland: 235
a) 60% b) 70 % c) 80% d) 90% 236
3) Somatotropic hormones consists of ____ amino acids 237
a) 121 b) 181 c) 191 d) none of these 238
4) Which hormone is also known as love hormone? 239
a) Vasopressin b) Oxytocin c) FSH d) b&c both 240
5) Which hormone helps in the production of milk? 241
a) Oxytocin b) prolactin c) epinephrine d) vasopressin 242

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Short questions: 243
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1. Write any three hormones of anterior lobe of pituitary and their target organs. (page no2) 245
2. What is the role of FSH in the men? ( line no 171 page no 10) 246
3. Why vasopressin is called so? (line no 195 page no 11) 247
4. Write any 3 functions of LH (line 184__187 page no 10) 248
5. What are the functions of epinephrine and nor-epinephrine? (line no 131 & 133 page no 7) 249
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Extensive question: 251
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1) Write any 3 hormones of pituitary gland with their physiological roles. 253
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