anatomy and physiology 2

notes before the first test

Classes of hormones

Steroid hormone

derived from cholesterol
examples estrogen and testosterone

hypothalamus -pituitary complex

Command center
Secretes lots of hormones

ADH

1 main hormone in water balance in the body
2 acts on kidney to absorb H2O back into the blood

Parathyroid glands

They are tiny and round and are embedded into the posterior surface and normally a person has 4 of them chief cells are found within the parathyroid glands

Nervous system

Controls muscles and glands

Classes of hormones

1. Amine hormones

Derived from an amino acid
Modified amino acid
Examples is: epinephrine and norepinephrine as well as thyroid hormones (T3 and T4)

Importance of receptors

Hormones only act of cells that have specific receptors

Oxytocin

1.causes uterine contraction
2.causes ejection of milk from female breasts
3.mother-newborn(bonding)
4.involved in feelings of love and closeness

Thyroid hormones functions

T3-triiodothyronine
Affects almost all tissues
T4- thyroxine
These classify as metabolic hormones

Calcitonin

Parafollicular cells (C cells)
Function:
Lowers blood calcium (Ca2+) by inhibiting osteoclasts
Promotes calcium (Ca2+) deposition into your bones

Zone 1

Zone 1 is zona glomerulosa
Outer part of cortex
Secretes
Mineralocorticoids
Aldosterone!
1 regulates blood pressure(BP)
2 regulate blood volume(BV)
3 regulates electrolyte balance in your body

Endocrine system

Controls nervous and other system (broad)

Neural signaling (AP)

Nervous system
Messages are sent through electrical signals
Example was messages going down as A.P to the muscle which releases acetylcholine
Neurotransmitters (electrical signals ie messages)
Very fast and short lasting
Effects are very specific and localized

Endocrine signaling

Uses the endocrine system
Glands secrete hormones
Hormones are the chemical messagers
Hormones travel through the blood stream
Slower and longer lasting
The effects are more widespread

Paracrine signaling

Acts on nearby cells
Effects are localized
Very important to cell to cell communication
They communicate through hormones to nearby cells

Autocrine signaling

Acts on same cell that releases the signal
The example was that the hormones travels through the bloodstream to get to the other cell it needs to communicate with

Classes of hormones

Peptide hormones

Short chain amino acids
Example was 7 amino acids in a straight line chain
Examples :ADH (antidiuretic hormones) and oxytocin

Classes of hormones

Protein hormones

Protein!!
Examples are growth hormones and FSH as well as LH

Hormone interactions

Hormones can interact in 3 ways
A) permissive effect
one hormone allows another hormone to work more effectively
Example is thyroid hormones increase the number of adrenaline receptors on cells allowing adrenaline to act more effectively!
B) Synergistic effect
Two hormones work together to produce a greater effect than either alone
Estrogen and FSH together stimulate follicles in your ovaries

C)Antagonistic effect
blocking receptors, altering metabolism, or opposing physiological processes

Regulation of hormone secretion

Levels of hormones are tightly controlled
1. negative feedback mechanism (most common)
Hormone secretion decreases when its effect reaches a certain level
2. positive feedback mechanism (less common)
Hormone secretion increases in response to its effect
3. chemical levels in the blood

4. neural stimuli
Brain can control hormone secretion
5 hormonal stimuli
One hormone stimulates the release of another hormone

Hypothalamus

Structure of Diencephalm
Neural and endocrine functions
Secretes hormones (endocrine functions is the secretes hormones)(also produces hormones)
Inhibiting hormones
Releasing hormones
They act on the anterior pituitary gland

1.Pituitary gland

Hypophysis
Size of a bean
suspended from a stem called infundibulum
Consists of 2 lobes
Anterior pituitary (epithelial tissue glandular is bigger then posterior one)
Posterior pituitary (made of nerual tissue)
Between lobes is the intermediate zone

Anterior pituitary

Contains 5 hormone secreting cells
1.Somatotrophs -(HGH)(growth hormone)-stimulates growth (bones and muscles) and regulates metabolism
2.thyrotrophs - thyroid-stimulating hormone ( TSH)- stimulates the thyroid gland to produce thyroid hormones (T3 and T4)
3.lactotrophs - prolactin (PRL)--causes milk production is female breast tissue
4.corticotrophs- Adrenocorticotropic (ACTH)--acts on the adrenal gland causing it to produce and secrete cortisol (i.e.. stress hormone)
5.gonatotrophs-Follicle-stimulating hormone(FSH)--stimulates ovarian follicle development and gamete production(male and female) and luteinizing hormone(LH)--stimulates ovulation in female!! and in male stimulates productions of testosterone!!

Students,Think,Looking,Cool,is Good

Posterior pituitary

Made of neural tissue (neuronal axons)
Releases hormones, BUT DOES NOT PRODUCE HORMONES!
DO NOT MAKE HORMONES
2 hormones released include
1.oxytocin
2.antidivertic hormone

Thyroid gland

Butterfly shaped
Anterior to trachea
Inferior to larynx
Middle region= is thmus
Tissue is composed mostly of thyroid follicles
Thyroid follicle
Follicular cells round the edge
Colloid is found in the middle ( is a sticky fluid)

Thyroid gland produces 3 hormones

1.T3 and T4
2.calcitonic
Follicular cells produce T3 and T4

Regulation of thyroid hormones

Hypothalamus secretes TRh thyroid releasing hormones and the the antertior pituitary gland (thyrotropes) T3H

Thyroid hormones functions part 1

1.Regulates your metabolism
Raises your basiometabolic rate (BMR)
Stimulate metabolism of carbs,fats,proteins
2.Effect your growth and development
Essential for normal growth
Required for nervous system development
Required for proper brown growth and maturation

Thyroid hormones functions part 2

3.effect cardiovascular system
Increase heart rate
Increase cardiac output
Increase force of heart contractions
They enhance the sensitivity to catecholamines

Thyroid hormones functions part 3

4.nervous system effects
Critical for alertness
Important for reflexes
Increase mental activity and responsiveness
5. Effects protein synthesis
Promotes protein synthesis

Chief cells

produce parathyroid hormone (PTH)

PTH functions
Causes release of CA2+ from the bone
Stimulates your osteoclasts
Also increases absorption of calcium(Ca2+) in the kidneys
PTH causes the production of vitamin D
Increases dietary calcium(Ca2+) reabsorption from the digestion system

Adrenal glands

Paired
Located superior to each kidney
Cortex produces steroid hormones
Medulla produces catecholamines "adrenaline"

Zone 2

Zone 2 fasciculata
middle ,thickest

Zone 3

zona reticularis
Inner most
Three zones of the cortex