Endocrine system Flashcards
Summarise the endocrine system…
The endocrine system coordinates the activity of organs through hormones - chemical messengers released into the blood from glands which produce them.
What are hormones?
Chemical messengers released into the blood from glands which produce them, which act on cells with the correct hormone receptors.
Hormones can be … name the three molecules.
- Peptides - water soluble proteins ie insulin
- Steroids - (cholesterol) sex hormones, cortisol
- Amino acid derivatives - adrenaline, thyroxine
Two systems ensure our survival by controlling homeostasis in two different ways. Name the two systems…
- Autonomic nervous system
2. Endocrine system
List the main differences between the autonomic nervous system and the endocrine system…
Autonomic nervous system creates RAPID change in the body, which is less precise with a shorter duration using neurotransmitters and controlled by the brains central nervous system.
Endocrine system creates a slower change but much more precise with the affects lasting longer. Functioning through hormones controlled by the hypothalamus.
Compare the two types of glands found in the body…
- Exocrine glands excrete products into ducts leading to body cavities, organs or skin. eg salivary glands, gastric glands, mammary glands
- Endocrine glands are ductless and secrete hormones directly into the bloodstream. eg pituitary, adrenals, thyroid
The endocrine includes 10 glands, name at least 7.
- Hypothalamus
- Pituitary
- Pineal
- Thyroid
- Parathyroid
- Adrenal
- Pancreatic : islets of langerhans (also exocrine)
- Thymus
- Ovaries
- Testes
Some tissues of the body are not considered glands but have endocrine function, as in, they produce hormones. Name them and the hormones they produce. (7)
- Adipose tissue - leptin ( suppresses food intake) Resistin (balances levels of blood glucose)
- Heart - atrial natriuretic peptide, helps control blood pressure
- GIT - Stomach - ghrelin and gastrin are the two main ones (satiety and gastric emptying)
- Liver - angiotensinogen (involved in blood pressure), Insulin-like growth factor IGF, thrombopoieten (hormone to make more platelets)
- Placenta - human chorionic gonadotropin (hCG) and progesterone (maintains pregnancy)
- Kidneys - erythropoietin (RBC production) and calcitriol (activating vit D)
- Skin - cholecalciferol - precursor for vit D
Hormones have specific target cells and influence the activity of the target cells by binding to specific receptors. Whats the difference between protein-based hormones and lipid hormones in regards to the cells receptors?
The receptors for Protein-based hormones are part of the cell membrane, whilst Lipid hormone receptors are within the cell.
Fill in the missing words…
Receptors allow hormones to have a 1._______ or 2._______ effect on different cell types.
- Stimulating
2. Inhibiting
The target cells can alter their sensitivity to the hormone; down regulation and up regulation - explain what this means….
Down regulation - if a hormone is present in excess, the target number of cell receptors may decrease
Up regulation - a deficiency in a hormone causes an increase in the number of receptors on the target cells.
Hormone secretions are regulated by 3 processes…name them
- Nervous system signals
- Chemical changes in the blood
- Other hormones
All interact to allow maximum flexibility in response to the environment.
They are controlled through positive and negative feedback loops.
Name the two lobes of the pituitary gland…
- Anterior pituitary gland
2. Posterior pituitary gland
The pituitary gland is often named the ‘master endocrine gland’ as it controls many other endocrine glands in the body.
It is self regulated and signalled by the ______
Hypothalamus
The hypothalamus and pituitary gland represent the major link between which two systems…
nervous system and endocrine system
The hypothalamus creates the signal for the pituitary gland to send. Name 5 releasing hormones…
- TRH - Thyroid releasing hormone
- GHRH - Growth hormone releasing hormone
- CRH - Corticotropin releasing hormone
- PRH - Prolactin releasing hormone
- GnRH - Gonadotropin releasing hormone
The hypothalamus creates the signal for the pituitary gland to send. Name 2 inhibiting hormones…
- GHIH - Growth hormone inhibiting hormone
2. PIH - Prolactin inhibiting hormone - also known as Dopamine
What is Dopamine?
Dopamine is a type of neurotransmitter. Your body makes it, and your nervous system uses it to send messages between nerve cells. That’s why it’s sometimes called a chemical messenger. Dopamine plays a role in how we feel pleasure. It’s a big part of our unique human ability to think and plan.
Aside from its “feel good” function, dopamine is involved in many body functions. These include:
blood flow digestion executive functioning heart and kidney function memory and focus mood and emotions motor control pain processing pancreatic function and insulin regulation pleasure and reward seeking behavior sleep stress response
the posterior lobe of the pituitary gland sends 2 hormones which are first synthesises in the hypothalamus, name the two hormones and their basic function…
- Oxytocin - bonding, uterus contraction and lactation.
2. Antidiuretic hormone (ADH) - urine output
The anterior lobe of the pituitary gland receives 7 hormones in capillaries from the hypothalamus, which are then synthesised and released. Name the 7
- Growth hormone (GH)
- Thyroid stimulating hormone (TSH)
- Follicle stimulation hormone (FSH)
- Luteinising hormone (LH)
- Prolactin (PRL)
- Adrenocorticotropic Hormone (ACTH)
- melanocyte stimulating hormone (MSH)
Corticotropin released by the hypothalamus which stimulates the anterior pituitary gland to release which two hormones….
- Adrenocorticotropic (ACTH)
2. Melanocyte (MSH)
Name the 4 main processes that Growth hormone activates…
- Regulates metabolism in many organs
- Stimulates the release of insulin-like growth factors (IGF’s) in cells
- Promotes growth and division of most body cells - especially bone and muscle
- Breaks down fats and glycogen
Growth hormone production is increased when… name 4 examples.
- During night time - growth hormone is increased during sleep
- Hypoglycameia - hypoglycemia (low blood sugar) produces an abrupt and sustained rise in levels of human growth hormone in plasma
- Exercise increases growth hormone - think muscle mass through weight lifting
- Childhood and adolescence - growth spurt
What is and where is the thyroid gland? Name the two hormones T3 and T4
The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). One of its main functions is to produce hormones that help regulate the body’s metabolism (the process that turns food into energy). These hormones are called triiodothyronine (T3) and thyroxine (T4).