THE ENDOCRINE SYSTEMPresented by: Quimson, Donna

Macapagal, Anna

ENDOCRINE SYSTEM

Are scattered masses of tissue found in various parts of the body. At the base of the brain, in the neck, behind the stomach, above the kidney and within and below the pelvis

ENDOCRINE SYSTEM

•The glands are controlled directly by stimulation from the nervous system as well as by chemical receptors in the blood and hormones produced by other glands.

•By regulating the functions of organs in the body, these glands help to maintain the body’s homeostasis.

•Cellular metabolism, reproduction, sexual development, sugar and mineral homeostasis, heart rate, and digestion are among the many processes regulated by the actions of hormones.

WHAT IS HOMEOSTASIS?

According to MORGAN (1961)

the homeostasis are the tendency of the body to maintain a balance among internal physiological conditions.

ANATOMY OF ENDOCRINE SYSTEMPituitary Gland, Adrenal Glands, Thyroid Glands, Parathyroid Glands, Pancreas and other glands.

Pituitary Gland

Pituitary Gland

•It is also known as the hypophysis

•It is a small pea-sized lump of tissue connected to the inferior portion of the hypothalamus of the brain.

•It has an anterior lobe and posterior lobe.

a. Anterior Pituitary Hormones

•Consists largely of epithelial cells

•Secretes the Growth Hormone(GH), Prolactin(PRL), Thyroid stimulating hormone, ACTH, FSH, and LH.

•Growth Hormone(GH) -Stimulates body cells to increase in size

and rate reproduction.

•Prolactin(PRL)-Promotes breast development and

stimulates breast production.

-In males, prolactin decreases the LM

•Thyroid Stimulating Hormone(TSH)-Controls the secretion of hormones from

the thyroid gland.

•Adrenocorticotropic hormone( ACTH)

•Follicle- stimulating hormone(FSH)

b. Posterior Pituitary Hormones

•Consists largely neuroglial cells and nerve fibers that originate in the hypothalamus.

•The two hormones of the posterior pituitary are produced in the hypothalamus.

•Antidiuretic Hormone(ADH)

- Causes the kidneys to reduce the amount of water they excrete.

- In high concentration, ADH causes blood vessel walls to constrict, thus raising BP or blood pressure.

- The secretion of the ADH is regulated by the hypothalamus.

•Oxytocin

- Has an antidiuretic effect and can cause muscles in the uterine wall to contract, thus playing a role in childbirth.

- Causes contraction of certain cells associated with production and ejection of milk from the milk glands of the breast.

Adrenal Glands

a. Structure of the Adrenal Glands•Also called as Suprarenal glands.

•Are small, triangular glands located on top of both kidneys

•Made up of two distinct layers ─ outer adrenal cortex and inner adrenal medulla.

b. Hormones of the Adrenal Medulla

• produces the hormones epinephrine and nor epinephrine

• these hormones are synthesized from tyrosine and are closely to each other.

• These hormones produce effects similar to those of Sympathetic Nervous System.

• Secretion of this hormone is stimulated by Sympathetic Nervous System.

c. Hormones of the Adrenal Cortex•Produces a variety of steroids that include

several hormones.

•Aldosterone- causes the kidneys to conserve Na ions

and later to excrete potassium ions.

- It is secreted in response to decreased Na ion concentration, increased K ion concentration.

•Cortisol- Maintains the synthesis of proteins,

promotes the release of fatty acids, and stimulates the formation of glucose from non- carbohydrates.

• Adrenal sex hormones- These hormones are male type although

some can be converted to female hormones.

- They are thought to supplement the sex hormones produced by gonads.

Parathyroid Glands

Thyroid Glands

•Is a butterfly-shaped gland located at the base of the neck and wrapped around the lateral sides of the trachea.

•The thyroid gland produces three major hormones─ Calcitonin, Tri-iodothyronine (T3) and Thyroxine (T4)

b. Thyroid Hormones•Thyroxin and tri- iodothyronine- Increase the rate of metabolism, enhance

protein synthesis, and stimulate the breakdown of lipids.

- Needed for normal growth and development , also for the maturation of the nervous system.

•Calcitonin- lowers the blood calcium and phosphate ion

concentrations.- Prevents prolonged elevation of calcium after

a meal.

Parathyroid Glands

Parathyroid Glands

•The parathyroid glands are 4 small masses of glandular tissue found on the posterior side of the thyroid gland.

•It makes Parathyroid hormone, which regulates the level of calcium in the blood, so that nervous and muscular systems can function properly.

Pancreas

a. Structure of the Pancreas• Is a large gland located in the abdominal cavity just

inferior and posterior to the stomach.

• It is a glandular organ in the digestive systemand endocrine system of vertebrates.

• The endocrine portion, which is also called the ‘Islets of Langerhans’ secretes glucagon, insulin and somatostatin.

• It is considered to be a heterocrine gland as it contains both endocrine and exocrine tissue.

b. Hormones of the Pancreas•Glucagon stimulates the liver to produce

glucose, causing an increase in the concentration of the blood glucose. It also promotes the breakdown of fats.

•Insulin promotes the movement of glucose through cell membranes, stimulates the storage of glucose, promotes the synthesis of proteins and stimulates the storage of fats.

GONADS

•Are the sex puberty glands w/ produe the sperm and eggcells for reproduction.

Other Endocrine Glands

Pineal Gland•The pineal gland is a small pinecone-shaped

mass of glandular tissue found just posterior to the thalamus of the brain.

•produces the hormone melatonin that helps to regulate the human sleep-wake cycle known as the circadian rhythm.

•The activity of the pineal gland is inhibited by stimulation from the photoreceptors of the retina.

Thymus

•The thymus is a soft, triangular-shaped organ found in the chest posterior to the sternum.

• The thymus produces hormones called thymosins that help to train and develop T-lymphocytes during fetal development and childhood.

Hypothalamus

•part of the brain located superior and anterior to the brain stem and inferior to the thalamus.

• It serves many different functions in the nervous system, and is also responsible for the direct control of the endocrine system through the pituitary gland.

Reproductive glands•The ovaries secrete estrogens and

progesterone.

•The Placenta secretes estrogens, progesterone, and gonadotrophin.

•The testes secrete testosterone.

IMPORTANT HORMONES IN HUMAN BODY

Melatonin hormone

•produced in the pineal gland and functions as an antioxidant and control sleep.

•Excess hormone melatonin can cause lethargy, liver disorders, eye disorders, fatigue, disorientation, psychotic thoughts and behavior, confusion, drowsiness, impaired speech, trembling, headache and dizziness.

Hormone Serotonin

•produced in the digestive tract.

•controls the mood or mood, appetite and sleep.

•Excess serotonin can cause anxiety, confusion, increased heart rate, dilated pupils, loss of muscle coordination, sweating, diarrhea, headache, chills, nausea, vomiting, convulsions, high fever, irregular heartbeat, uncontrolled movements and loss of consciousness.

Thyroid hormones

•produced in the thyroid gland.

•serves to increase the basal metabolic rate and affects protein synthesis.

•Excess thyroid hormone can cause diarrhea, irregular heartbeat, headache, chills, nervousness, stomach cramps, fever, chest pain, or difficulty sleeping.

Adrenal hormones• It is produced in adrenal medulla

•This hormone serves to increase the supply of oxygen and glucose to the brain and muscles (by increasing heart rate), increasing catalysis of glycogen in the liver, damage to lipids in fat cells, and suppresses the immune system.

•Lack of adrenal hormones may cause dizziness, headache, fatigue, weight loss, several intestinal disorders, increased pigmentation of the skin, depression, muscle pain and acute pain.

Hormone Dopamine•produced in kidney and hypothalamus.

•serves to increase the heart rate and blood pressure, inhibiting the release of prolactin and TRH from anterior pituitary.

•Excess dopamine can cause nausea, vomiting, headache, irregular heartbeat, chest pain, difficulty breathing, changes in amount of urine, skin discoloration, pain in legs and arms.

Gastrin hormone

•This hormone is produced in the duodenum (intestine 12 fingers), the which serves for gastric acid secretion by parietal cells.

growth hormone•produced in the anterior pituitary and serves

to stimulate the growth and reproduction of cells, releasing the insulin-like growth factor 1 from the heart.

•This hormone deficiency in children can cause growth failure and short body and delayed sexual maturity. Whereas in adult growth hormone deficiency is rare, but in some cases can lead to obesity, decreased muscle mass and energy reduction and quality of life.

Insulin hormone

•This hormone is produced in the pancreas and serves to glucose uptake, glycogenesis and glycolysis in liver and muscle of blood.

•Insulin deficiency can lead to hyperglycemia (elevated blood sugar) which can lead to diabetes mellitus.

Testosterone hormone

•This hormone is produced in the testes and serves as the male sex hormone. This hormone stimulates the maturation of male sex organs, scrotum, beard growth, the growth of muscle mass and strength, and increase bone density.

Progesterone hormone•This hormone is produced in the ovaries,

adrenal glands and the placenta (during pregnancy).

•serves to raise the epidermal growth factor, increases core temperature during ovulation, reduces spasm and relaxes smooth muscle (extending the respiratory tract and regulate mucus), anti-inflammatory, reduces gall bladder activity, normalization of blood and clotting of blood vessels.

• Source: rejekine.blogspot.com

THE SENSESSense of sight, touch, hear, taste and smell

The Senses

•Aristotle (384 BC - 322 BC) is credited with the traditional classification of the five sense organs: sight, smell, taste, touch, and hearing.

•Immanuel Kant proposed that our knowledge of the outside world depends on our modes of perception. In order to define what is "extrasensory" we need to define what is "sensory".

•Each of the 5 senses consists of organs with specialized cellular structures that have receptors for specific stimuli. These cells have links to the nervous system and thus to the brain.

•Sensing is done at primitive levels in the cells and integrated into sensations in the nervous system.

Sense of sight

EYES-Has five main parts: the cornea, the pupil, iris, lens and retina.

Structure of the eye• CORNEA- Transparent covering in front of the eye where light

enters.- sharply curved and serves as a preliminary lens,

helping focus the light

• PUPIL- Located behind the cornea- The opening in the center of the eye that appears black.

• IRIS- A ring muscle whose pigmentation gives the eye its

color.

• LENS- Light passes trough a transparent

structure called the lens.- The ciliary muscles attached to the lens

modify its curviture to focus the light so that it makes a clear image in the retina.

•RETINA- Surface at the back of the eye- It is where the sense receptors for light

are located in the retina─ rods and cones.

•Rods and Cones- Transform the electromagnetic energy of

light into neural impulses which are in turn transmitted to the brain by the optic nerve, leaving the retina at the back of the eyeball.

- the area of the retina where the optic nerve leaves the eye does not have any photoreceptors. It is referred as the blind spot, since there is no visual response to the light that strikes this area.

•Fovea- Small area in the center of the retina

which contains only cones while the area at the edge of the retina contains only rods.

- The area between the fovea and the edge contains both rods and cones.

- There are 100- 130 million rods and 6- 7 million cones in the retina of each eye.

Color Vision

•Color perception is a complex process that depends on psychological and physiological processes.

•Two major explanations, the trichromatic theory and the opponent- process theory.

a. Trichromatic theory• was first advanced in the 19th century by Thomas

Young and later elaborated by the physiologist, Herman von Helmholtz.

• Color vision is based on three types of cones thought to be mingled in a mosaic pattern throughout the central retina.

• The proportion of each kind of cone activated determines the color that is percieved.

• Any color of the visible spectrum can be produced frome some combination of the three kinds of cones.

b. Opponent- process theory•Developed by Ewald Hering•based on the ways people describe colors

rather than on the mixing of colored lights.•Hering used the phenomenon of after- images

to support his view that these four colors are paired into opposing combinations: red- green and yellow- blue.

•There are 3 types of cones─ one that respond to brightness, one that responds to red- green, and the one that responds to yellow- blue.

Night Blindness

•During the daylight hours, they have normal vision but as the light dims and the period of twilight begins, they lose their sight.

•People with night blindness lose their sight under low levels of illumination because their retinas contain no rods or no functioning rods.

Sense of hearing•EARS- Has three main parts: outer ear, middle ear, and the inner ear.

Structure of the Ear•The ear has 3 major divisions: 1) the outer ear- the external projecting

portion, called the pinna and the auditory canal

2) The middle ear- separated from the outer ear by the eardrum and containing three small bones connectively called ossicles

3) The inner ear or cochles- the 3 semi- circular canals, located in the inner ear, are not part of the auditory system; they provide cues to body position and movement.

Sense of taste

Sense of taste

•The receptors for taste, called taste buds, are situated chiefly in the tongue, but they are also located in the roof of the mouth and near the pharynx.

•They are able to detect four basic tastes: salty, sweet, bitter, and sour. The tongue also can detect a sensation called "umami" from taste receptors sensitive to amino acids.

Sense of smell

OLFACTORYPERCEPTION/OLFACTION

1: Olfactory bulb2: Mitral cells3: bone4: Nasal epithelium5: Glomerulus6: Olfactory receptor neurons

Sense of Smell• Olfaction or Olfactory perception• A form of chemical perception• The nose is the organ responsible for the sense of smell.• Olfactory receptions: used to detect the presence of smell.• Glomerulus: a structure which transmits signals to the olfactory bulb.

•Many vertebrates, including most mammal and reptiles have two main distinct olfactory systems─ main olfactory system and accessory olfactory system.

•For air-breathing animals, the main olfactory system detects volatile chemicals, and the accessory olfactory system detects fluid-phase chemicals.

•Odorants: the chemicals that activate the olfactory system

• Volatile small molecule odorants, non-volatile proteins, and non-volatile hydrocarbons may all produce olfactory sensations.

• In vertebrates smells are sensed by olfactory sensory neurons in the olfactory epithelium.

• Humans have about 10 cm2 (1.6 sq in) of olfactory epithelium

• Each receptor cell has a single external process that extends to the surface of the epithelium and gives rise to a number of long, slender extensions called cilia.

•Cilia: facilitating the detection of and response to odour molecules by olfactory receptors.

•FUNCTION OF OLFACTORY SYSTEM: to smell, when odour is inhaled it goes through the olfactory epithelium which contains about 20 million nerve endings which are connected to the brain for processing. The complex structure of the olfactory system has the ability to dredge up memories or even change moods after a particular odour has been processed and identified.

Disorders of Olfaction• Anosmia – inability to smell• Dysosmia– things smell different than they should• Hyperosmia – an abnormally acute sense of

smell.• Hyposmia – decreased ability to smell• Olfactory Reference Syndrome – psychological

disorder which causes the patient to imagine he or she has strong body odor

• Parosmia– things smell worse than they should be.

• Phantosmia – "hallucinated smell," often unpleasant in nature

Sense of touch

Sense of touch

•The sense of touch is distributed throughout the body

•Four kinds of touch sensations can be identified: cold, heat, touch, and pain.

•SKIN- Has two main layers: epidermis and

dermis- the bottom layer is called subcutaneous

tissue.

SKIN

•Epidermis- consists of layers of skin cells with free nerve

endings.

- the epidermis is waterproof and serves as a protective wrap for the underlying skin layers and the rest of the body.

- It contains melanin, which protects against the sun's harmful rays and also gives skin its color.

-contains very sensitive cells called touch receptors.

•Dermis-includes sweat glands, blood vessels, hair

follicles, smooth muscles, and various sense receptors.  

- filled with many tiny nerve endings which give you information about the things with which your body comes in contact.

•Subcutaneous tissue- Composed of fat and connective tissues- The layer of fat acts as an insulator and helps

regulate body temperature. It also acts as a cushion to protect underlying tissue from damage when you bump into things.

- The connective tissue keeps the skin attached to the muscles and tendons underneath.

Kinds of touch sensations

•Warmth and Cold- Felt when the skin is touched with

stimulators that are at skin temperature, usually 32 degrees Celcius.

- Warmth is felt at temperatures greater than physiological zero

- Cold is felt at temperature lower than physiological zero.

•Touch- Sensitivity to touch varies enormously

over different portions of the body.

•Pain- Many kinds of stimuli─ scratch, puncture,

pressure, heat, cold- twist─ can produce pain.

- The experience of pain is greatly influenced by emotional factors.

- they can protect you by warning your brain that your body is hurt.