Lecture 23 Flashcards
Communication between cells is essential to
Coordinate homeostatic response
Nervous syst uses what to communicate, allowing very quick communication between receptor effector and cc
Electrical signals
Endocrine uses what to communicate bet cells rather than electrical impulses
Signal molecules (hormones)
Hormones in blood sugar regulation
Glucagon and insulin
Blood glucose rises steps
- Stimulus: blood glucose rises
- Beta cells in pancreas release insulin in blood
- Insulin tells liver and body cells to take up glucose
- Liver stores it as glycogen
- Blood glucose level declines
- Homeostasis
Blood glucose drops steps
- Stimulus: blood glucose drops
- Alpha cells in pancreas release glucagon in blood
- Glucagon tells liver to break down glycogen to release glucose
- Blood glucose level rises
- Homeostasis
Nervous vs endocrine (N vs E): method of communication
N: electrical impulses and neurotransmitters
E: hormones
N vs E: speed of communication
N: very fast (milliseconds)
E: fast to slow (seconds to minutes)
N vs E: duration of effect
N: very short duration (ex muscle contraction)
E: longer, ranges from seconds to days (ex menstrual cycle)
N vs E: responses voluntarily/involuntarily
N: voluntary or involuntary
E: involuntary only
N vs E: potential effectors
N: all muscle types and glands (both exocrine and endocrine)
E: any cell in body (the provided cell has receptors for at least one hormone)
Hormone communication is performed by
Secreting and receiving hormones
what are called cells that secrete hormones
Endocrine cells (part of a grp of similar cells within an endocrine gland)
Hormones circulating steps
- Hormone secreted by endocrine cell
- Enters blood via capillary
- Travels throughout cardio syst
- Reaches many/all tissues of body
- ONLY cells with receptors for that hormone will respond to it (target cells)
Target cells
- Cell that has a specific receptor on/in it for a hormone to bind to
- Can be located anywhere, many target cells for particular hormones
- Target cells can have receptors for different types of hormones
Glands of endocrine system
- Pineal gland
- Pituitary gland
- Thyroid gland
- Parathyroid glands
- Adrenal glands
- Pancreas
- Testis/ovary
What is the control center of endocrine system
Hypothalamus
Hypothalamus targets what gland
Pituitary (in turn influences numerous body functions)
What integrates both nervous and endocrine systems
Hypothetically
Pituitary gland referred to as
Master gland (bc controls large portion of endocrine activity)
What gland secretes several different hormones that regulate several different glands/organs
Pituitary
Pituitary gland lobes
Anterior and posterior
Anterior lobe pituitary gland hormones
- Musculoskeletal: GH (growth hormone)
- Mammary glands: PRL (prolactin )
- Ovary: FSH (follicule-stimulating hormone), gonadotropin
- Testis: LH (luteinizing hormone), gonadotropin
Posterior lobe pituitary gland hormones
- Kidney: ADH (antidiuretic hormone)
- Uterus: OXT (Oxytocin)
Childbirth oxytocin steps
- Head of baby pushes against cervix
- Nerve impulses from cervix transmitted to brain
- Brain stimulates pituitary gland to secrete oxytocin
- Oxytocin carried in bloodstream to uterus
- Oxytocin stimulates uterus contractions and push baby towards cervix
Relationship between nervous and endocrine in childbirth
When head pushes on cervix, sensory neuron sends impulse to hypothalamus that tells pituitary to release oxytocin
ADH tells kidney what
How much water to conserve
Kidneys adjust amount if water put in urine based on
Amount of ADH secreted by pituitary gland
When dehydrated, little water in urine bc
ADH secreted, which tells nephrons to retain water in blood
When well hydrated, ADH secreted or not
No, kidney produce very diluted urine
Alcohol inhibits what
ADH secretion, so inability to retain water even when dehydrated
Color of urine/ADH relation
More ADH = less water in urine = dark color
Hormones controlling secretion and processes of body’s reproductive organs (ex menstrual cycle)
Gonadotropins: follicle stimulating hormone, luteinizing hormone
What does growth hormone do
Stimulates growth, increase in cell size and number of
GH conditions (treated with growth hormones in lab)
- Gigantism: high production of GH in childhood when bones still growing
- Pituitary dwarfism: insufficient production of GH in childhood
When insuline released, reaches cells with receptors that detect it and will allow glucose to enter them by
facilitated diffusion
Insulin target cells
Liver, muscle and fat cells (make glucose into glycogen)
Target cells of glucagon
Liver cells only (release glucose back in body by hydrolysis of glycogen)
Antagonistic hormones are
Pairs of hormones that trigger exact opposite responses
Ex glucagon and insulin
Type 1 DM
Pancreas cells destroyed by own immune syst (autoimmune disorders), so failure to produce insulin
Type 2 DM
Cells fail to respond to insulin, risk factors to develop it include HTN, obesity, lack of exercise
In both cases of DM, cells don’t take glucose from blood, so very high which can lead to
High bp and if untreated, widespread damage of capillaries/surrounding tisues
When stressed (sympathetic response), electrical impulse sent to adrenal gland to
Secrete epinephrine (adrenaline) into blood which intensifies stress response
Kidneys and adrenal glands function
Independently
