Lab # 1 Endocrine System. THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW. THERE MIGHT BE THINGS...
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Transcript of Lab # 1 Endocrine System. THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW. THERE MIGHT BE THINGS...
Lab # 1
Endocrine System
THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW.
THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BE ASKED IN YOUR QUIZZES and PRACTICAL TESTS.
STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR MANUAL AND FOR ALL THE MATERIAL COVERED DURING THE LABORATORY PERIOD, AS PER THE COURSE SYLLABUS
There are Two Organ Systems Dedicated to Maintaining the Internal Conditions (Homeostasis):
It employs electrical and chemical means to send messages from cell to cell.
1- Nervous System
2- Endocrine System It communicates by means of chemical messengers (hormones) secreted into to the blood.
Endocrine gland
Target cell (skeletal muscle cell)
Hormone
Target cell (skeletal muscle cell)
The Hypothalamus and the Pituitary GlandThe hypothalamus and the pituitary gland have the greatest influence in regulating the entire endocrine system.
Pituitary gland
Hypothalamus
Thalamus The hypothalamus secrets releasing hormones that trigger secretions of the anterior pituitary gland.The pituitary gland
secrets hormones that control other glands.
Corpus callosum Septum pellucidum Fornix
Pineal gland
Anterior commissure
Thalamus
Intermediate mass
Hypothalamus Mamillary bodyOptic chiasm
Pituitary gland
Epi- thalamus
Infundibulum
Three Mechanisms of Hypothalamic Control over Endocrine Function
Secretion of regulatory hormones to control activity of anterior lobe of pituitary gland
1
Production of ADH and Oxytocin2
Control of sympathetic output to adrenal medulla3
Tropic hormones secreted by anterior lobe of pituitary gland control other endocrine organs
Release of ADH and oxytocin
Secretion of epinephrine and norepinephrine
Anterior lobe or Adenohypophysis:
Anterior Posterior
Third ventricle of brain
Pars tuberalis (around the infundibulum)
Pars distalis(main portion of anterior lobe)
Infundibulum (stalk)
Posterior lobe, Neurohypophysis or Par nervosa
Hypothalamus:
Pars intermedia(in the interior)
Anatomy of the Hypothalamus and the Pituitary Gland
PRLProlactin (PRL)
After birth stimulates the mammary glands to synthesize milk.
Thyroid-stimulating hormone (TSH)
It stimulates secretion of thyroid hormone.
TSH
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Gonadotropins:
It stimulates the development of ovarian follicles, secretion of ovarian sex hormones, and sperm production.
It stimulates ovulation, stimulates corpus luteum to secrete progesterone, stimulates testes to secrete testosterone.
FSHLH
ACTH
It stimulates the adrenal cortex to secrete glucocorticoids.
Adrenocorticotropic hormone (ACTH)
GH
Liver
Fat,muscle,bone
It stimulates mitosis and cellular differentiation and thus promotes tissue growth throughout the body
Growth hormone (GH)
The Anterior Pituitary Produces Seven
Hormones
Releasing hormones are produced by the hypothalamus .
Releasing hormones target the anterior pituitary (adenohypo-physis )
Melanocyte stimulating hormone (MSH)
Releasing hormones
It stimulates the melanocytes of skin to produce melanin.
MSH
Oxytocin (OT)
Posterior pituitary or Neurohypophysis stores and
releases:
It stimulates uterine contractions and propulsion of semen.
It stimulates labor contractions during childbirth.
Antidiuretic hormone (ADH)
It increases water retention thus reducing urine volume and prevents dehydration.
It is also called vasopressin because it can cause vasoconstriction.
Oxytocin (OT)
Antidiuretic hormone (ADH)
Oxytocin (OT)
Antidiuretic hormone (ADH)
The Hypothalamus Produces two Hormones: Oxytocin (OT) and Antidiuretic Hormone
2- Thyroid Gland
Right lobe
Left lobe
Isthmus
T4 or Thyroxine
T3 or Triiodothyronine
Calcitonin
Thyroid Hormones
1- T4 or thyroxine
2- T3 or triioodothyronine
Follicular hormones (they are produced by the follicular cells)
1- They increase the rate of oxygen uptake and the basal metabolic rate
2- They enhance the effects of sympathetic stimulation (increasing heart rate, blood pressure, nervousness, and sweating)
3- They help to maintain body temperature
4- They help to regulate growth, development, and intracellular metabolism by increasing protein synthesis and lipid breakdown
5- They stimulate RBC formation, and speed up bone turnover
1- T4 or thyroxine
2- T3 or triiodothyronine
3- Calcitonin
3- Calcitonin
It is released in response to high levels of calcium in the blood
Calcitonin hormone is released by thyroid gland
Inhibits osteoclasts to resorb bone, and encourages calcium salt deposit in bone matrix
[Calcium] in blood
[Calcium] in blood
3- Parathyroid Glands
Thyroid gland, posterior view
Parathyroid glands
Parathyroid glands
The Parathyroid Hormone
It increases calcium blood levels by targeting bone and kidneys
[Calcium] in blood
Parathyroid hormone is released by parathyroid gland
Stimulates the osteoclasts to resorb bone, releasing calcium to the blood
[Calcium] in blood
1- In bones
2- In kidneys
- It increases calcium reabsortion
- It increases formation and secretion of calcitriol Increases absorption of
calcium and phosphate from the intestines
[Calcium] in blood
4-Thymus GlandThe thymus is located in the mediastinum.It atrophies after puberty.The thymus is divided into two thymic lobes.Septa divide lobes into smaller lobules.
Functions:
T cells migrate into medulla. Mature T cells leave thymus by medullary blood vessels.
1- It secretes thymic hormones that stimulate stem cell divisions and T cell differentiation.
The lymphocytes divide in the cortex.
5- Suprarenal Glands
Mineralocorticoids(Aldosterone)
Glucocorticoids(Cortisol, Cortisone and
Corticosterone)
Sex hormones( androgens)
Medulla (It is considered part of Sympathetic Autonomic nervous System)
Catecholamines(Epinephrine and Norepinephrine)
Hormones of the Adrenal Cortex1- Mineralocorticoides (Aldosterone)
-It increases sodium and water reabsortion in kidneys
-It increases potassium secretion in kidneys
Aldosterone secretion is regulated by the renin-angiotencin mechanism
Blood pressure or plasma solute concentration
Renin-angiotencin mechanism
Aldosterone secretion
2- Glucocorticoids (Corticosterone and Cortisol)
-They help the body to resist stressors
-They depress the immune system and the inflammatory response
3- Gonadocorticoids or Sex Hormones (Androgens)
-They are masculinizing hormones. - In females they stimulate sexual drive. After menopause they are
converted to estrogens.
Blood Pressure
-Blood glucose levels
They increase:
-Cardiac activity
-Blood pressure
-Glycogen breakdown
-Triglyceride breakdown
Hormones of the Adrenal Medulla
Catecholamines(Epinephrine and Norepinephrine)
6- Pancreas
Endocrine pancreas Exocrine pancreas
Pancreatic acini
They secrete large quantities of an alkaline, enzyme rich fluid
1- Beta cells:
2- Alpha cells:
3- Delta cells:
4- F cells:
Insulin
Glucagon
Somatostatin
Pancreatic polypeptide
Islets of Langerhans
Pancreas
1- Glucagon (released by alpha cells)
Liver Blood glucose
2- Insulin (released by beta cells)
(beta cells) Insulin
- It increases the rate of glucose uptake by cells
- It increases cellular metabolism
- It increases the storage of lipid and glycogen
- Increases aminoacids absorption and protein synthesis
-It stimulates the liver to produce glucose
-It stimulates to breakdown glycogen
Glucagon
Blood glucose
Pancreas( alpha cells)
- Blood glucose
Blood glucose
Interstitial cells Sustentacular cellsThey produce Androgens
(testosterone) They produce Inhibin
Androgens: They promote maturation of male sexual organs, and production and maturation of sperm
Inhibin: It inhibits the secretion of FSH
The Testes Germ cellsThey become spermatozoa
7- Testes and Ovaries
The Ovaries
Primary oocytes
Primary follicles
Secondary follicles
Tertiary follicles
Corpus luteum :
Follicles: Estrogens
Progesterone
Prepares the uterus for implantation
Establishes the menstrual cycle
Maintains pregnancy
Prepares mammary glands for milk secretion
Stimulate development of the secondary sexual characteristics
Stimulate follicle maturation
Stimulate maturation of the female re[productive system
The Ovaries
7b- The Ovaries