Endocrinology Flashcards
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Direct communication
- Transportation via gap junctions or connexins
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/323/965/q_image_thumb.png?1551353380)
Contact communication
- Information processing via molecules integrated into the membrane
- Typical in cells of the immune system
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/323/970/q_image_thumb.png?1551353414)
Communication by secretion
- Cells are located relatively far away
- Molecules are secreted and received
- Typical of the immune and nervous system
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/324/041/q_image_thumb.png?1551353441)
Cytoskeletal communication
- Metabolism of a cell is influenced
- This is relayed by the cytoskeletal system
Give the types of cell communication
- Direct communication
- Contact communication
- Communication by secretion
- Cytoskeletal communication
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/324/513/q_image_thumb.png?1551354297)
Classical endocrine effect
- Cells secrete hormones
- Hormones reach recipient cells via blood stream
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/324/686/q_image_thumb.png?1551354442)
Paracrine effect
- Signals do not enter the blood
- Acting on cells of the same tissue adjacent to the original cell
- Signals are called local chemical mediators
Give the fate of local chemical mediators in the paracrine system
They can be either:
- Broken down
- Immobilised
- Taken up by cells
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/324/958/q_image_thumb.png?1551355025)
Autocrine effect
- A special form of paracrine effect
- Signal-producing cell sends and receives its own signals
List the types of information processing in the endocrine system
- Classical endocrine effect
- Paracrine effect
- Autocrine effect
- Neurotransmitters
Which part of the CNS is the integrator of the endocrine system?
The hypothalamus
The function of the hypothalamus in the endocrine system depends on…
- The levels of hormones
- Information arriving from:
- Nervous system
- Immune system
Title this figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/326/919/q_image_thumb.png?1551357228)
Feedback within the endocrine system
What is the function of the feedback mechanism in the endocrine system?
It allows fine-tuning in the regulation of signals
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/053/q_image_thumb.png?1551357332)
Hypothalamus
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/096/q_image_thumb.png?1551357363)
Pituitary gland
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/120/q_image_thumb.png?1551357382)
Target organ
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/135/q_image_thumb.png?1551357413)
“Smart” end-users: Peripheral cells
Give the classifications of endocrine feedback mechanisms
- Long feedback
- Short feedback
- Ultra-short feedback
Give an example of where long feedback occurs
Between:
- A peripheral gland
- Hypothalamus
Give an example of where short feedback occurs
Between:
- A peripheral gland
- Pituitary gland
Give an example of where ultra-short feedback occurs
Between:
- Hypothalamus
- Pituitary gland
Which hormones are used to demonstrate the classical regulatory pathway?
Thyroid hormones
Title this figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/447/q_image_thumb.png?1551358131)
Thyroid feedback
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/608/q_image_thumb.png?1551358166)
Hypothalamus
TRH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/639/q_image_thumb.png?1551358225)
Hypophysis
TSH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/642/q_image_thumb.png?1551358383)
Thyroid gland
Thyroxine synthesis increases
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/816/q_image_thumb.png?1551358422)
Blood vessel:
Thyroxine level increases
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/841/q_image_thumb.png?1551358829)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/327/841/a_image_thumb.png?1551358849)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/328/103/q_image_thumb.png?1551358875)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/328/103/a_image_thumb.png?1551358910)
Give examples of IC “second messengers”
- cAMP
- cGMP
- Ca2+
- Diaglycerol (DAG)
- Inositol triphosphate (IP3)
Which processes occur between:
- Signals being received
- The appearance of biological effects
Signal transduction processes
What are the reasons that a hormone-like substance could have varying effects on different cells?
- There are separate receptors in the different tissues
- The receptor is the same but a different signalling pathway is initiated
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/328/672/q_image_thumb.png?1551360219)
Scatchard analysis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/329/116/q_image_thumb.png?1551360266)
Bmax (No. of binding sites) given by the point of intersection
What is a Scatchard analysis used for?
Used for measuring the properties of receptor-ligand interaction
Which parameters can be estimated from a Scatchard analysis?
- The total number of binding sites
- Strength (affinity) of binding between the receptor and the ligand
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/329/524/q_image_thumb.png?1551361373)
Regulation of receptor number
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/330/044/q_image_thumb.png?1551361400)
- Either:
- Long lasting hormone treatment
- The decrease of cellular metabolic needs
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/330/103/q_image_thumb.png?1551361465)
“Down-regulation”
Inhibition of receptor expression
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/330/128/q_image_thumb.png?1551361504)
Either:
- Removal of the endocrine gland
- Increase of cellular metabolic needs
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/673/472/q_image_thumb.png?1551691238)
“Up-regulation”
Facilitation of receptor expression
How do lipophilic hormones have an effect on cells?
- They easily pass the cell membrane
- Binding to cytoplasmic proteins
- They then reach the nucleus
- Modification of genetic expression of proteins
How do water-soluble/hydrophilic peptides and glycoprotein hormones have an effect on cells?
Exert actions by binding to membrane surface receptors
G-protein dependent transduction outcomes
- Migration of G-protein to ion channel protein, activating/inactivating it
- Activate enzymes bound to the IC side of the membrane
- Influence adenylate cyclase activity → IC cAMP conc.
- Control phospholipase C activity → Produces messengers
- Control PLA2 enzyme → Arachidonic acid
Describe the receptor of G-protein independent transduction
The receptor is a transmembrane protein:
- EC ligand binding part
- Central part
- IC part which exhibits phosphorylase activity
Describe G-protein independent transduction
- Ligand bond formation
- IC polypeptide chain phosphorylates
- Receptor activates
- Biological action
Describe cell activation when the receptor is in the cytoplasm
- Lipophilic hormones pass the cell membrane
- Hormones bind to cytoplasmic proteins (receptors)
- Receptor-ligand complex formation
- DNA-binding domain of the receptor protein ‘finds’ HRE
- Biological response initiated through transcription of a protein
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/677/396/a_image_thumb.png?1551695497)
Title the figure
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Fine structure of the nuclear receptor
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/678/287/q_image_thumb.png?1551695748)
Lypophilic hormone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/678/333/q_image_thumb.png?1551695791)
LBD
Ligand binding domain
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/678/356/q_image_thumb.png?1551695815)
DNA-BD
DNA binding domain
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/678/382/q_image_thumb.png?1551695923)
HRE
Hormone-responsive element
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/678/479/q_image_thumb.png?1551695973)
BPE
Basal promoter element
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/678/539/q_image_thumb.png?1551696006)
VD
Variable domain
The function of the VD
Locating of the base-pair segment of the DNA
Specific to the particular hormone
The function of HRE
Binds the DBD
DBD
DNA binding domain
Amino acid segment of the hormone-receptor complex
The function of the BPE
- Activated by receptor-DNA complex
- Expression of the structural gene begins
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/679/863/q_image_thumb.png?1551696588)
The receptor in the form of an ion channel
Describe the structure of a receptor which is acting as an ion channel
- 5 membrane-integrated domains
- Ligand binding site on the EC side
- 2x alpha subunits
- 2x beta subunits
- 1x delta subunit
Give examples of receptors which are ion channels
- n-ACh-R (Nicotinic acetylcholine receptor)
- Glutamate receptors
- Anion receptors
Nicotinic acetylcholine receptors can be inhibited by…
d-tubocurarine
n-ACh-R can be stimulated/inhibited by substances affecting the…
Receptor’s 5 subunits
What are the states n-ACh-R can be in?
- Closed (before ACh binding)
- Open (After ACh binding)
Describe the processes after ACh binds to the receptor
- Conformational change
- Cation channel opens (“open state”)
- Flow of cations
- Local excitatory potential formed
- AP is triggered
Describe the closing of n-ACh-R
- The open channel becomes inactivated
- Ligand bond still exists
- Change of conformation doesn’t allow cation flow
- Channel is “inactive”
- Dissociation of the ligand
- Channel closes
Give the main groups of glutamate-sensitive receptors
- NMDA receptor
- AMPA receptor
- Kainate-receptor
NMDA receptor
- Function
N-metil-D-aspartate
- Binding Mg2+ keeps receptor closed
- Mg2+ dissociated after receptor activation
- Ca2+ influx maintains a lasting effect
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/692/192/a_image_thumb.png?1551710061)
Opening of anion-receptors causes
Hyperpolarisation of CNS inhibitory synapses
What can cause hyperpolarisation of anion receptors
Nonspecific anions
- Cl-
- HCO3-
Give the main mediators of anion-receptors
- GABA
- Glycine
The function of GABA in the anion-receptor
- Either GABA-A / GABA-B
- GABA-B activation:
- Decrease IC cAMP
- Affects K+ channels
G-protein structure
- 3 subunits form a complex:
- Alpha subunit + GDP
- Beta subunit
- Gamma subunit
G-protein mechanism of action
- The ligand binds to the EC receptor
- Conformational change in the 7-M protein
- Beta + gamma subunits bind to the IC side of the receptor
- Alpha subunit conformational change
- Alpha subunit binds GTP
- Alpha subunit-GTP complex liberated
- Stimulates/inhibits ion channel/enzyme
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/694/268/a_image_thumb.png?1551714253)
Describe the return of G-protein to its resting state
- GTP → GDP
- Alpha subunit binds to gamma + beta again
- G protein → Resting state
Describe Gs effect
- Activated G-protein migrates to a remote ion channel protein
- Activates the channel
Describe Gi effect
- Activated G-protein migrates to a remote ion channel protein
- Inactivates the channel
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/015/q_image_thumb.png?1551714603)
- M2 ACh-R
- K+ channel opens
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/136/q_image_thumb.png?1551714623)
- alfa2 type R
- K+ channel opens
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/252/q_image_thumb.png?1551714671)
- D2 type R
- K+ channel opens
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/290/q_image_thumb.png?1551714736)
- GABA type R
- K+ channel opens
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/322/q_image_thumb.png?1551714772)
- S2 type R
- K+ / Ca2+ channel opens
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/360/q_image_thumb.png?1551714816)
- OP type R
- Ca2+ channel opens
Title this figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/698/467/q_image_thumb.png?1551715825)
Adenylate cyclase mechanism
Summarise the adenylate cyclase mechanism
- Influenced by G-proteins
- Gs: adenylate cyclase activity ↑
- Gi: adenylate cyclase activity ↓
Describe the steps of the Gs mechanism
- Glucagon mobilises Gs G-protein
- Liberates hepatic glycogen stores
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/699/673/a_image_thumb.png?1551716596)
Describe the steps of the Gi mechanism
- alpha2-adrenergic receptor activated
- IC cAMP levels ↓
List receptors of the Gs pathway
- Prostacyclin
- Dopamine D1
- Catecholamine beta
- Anterior pituitary
- Histamine H2
- 2-type ADH
List receptors of the Gi pathway
- Dopamine D2
- Alpha1 catecholamine
- Some glutamate
- Some opioid
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/701/242/q_image_thumb.png?1551716870)
Phospholipase C mechanism (PLC)
Give the steps of the phospholipase C (PLC) mechanism
- Activation of G-protein
- Stimulates Phospholipase C
- Converts membrane phospholipids → IP3/DAG
IP3
- Binds to IP3 receptor (on the surface of Ca2+ sequesters)
- The receptor is an ion channel
- IP3 opens the channel
- Increasing IC Ca2+
- Cellular effects
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/703/323/a_image_thumb.png?1551718708)
DAG
- Similar behaviour to cAMP
- Activates type-C protein kinases
- Triggers several phosphorylation pathways
- Biological effects
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/703/613/a_image_thumb.png?1551718782)
Give examples of ligands in the PLC mechanism
- ACh
- Histamine
- Purin
- PGE
- TXA2
- ADH
- Oxytocin
All of which release Ca2+
Give the steps of the Phospholipase A2 (PLA2) mechanism
- G-protein activation
- Converts phospholipids → arachidonic acid (substrate)
- Arachidonic acid → Several products
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/704/841/a_image_thumb.png?1551719294)
Besides active G-proteins, what else can activate the PLA2 mechanism?
Ca2+
Arachidonic acid can pass through which further pathways?
- Lipoxygenase pathway
- Cyclooxygenase pathway
- Epoxygenase pathway
List the products of the lipoxygenase pathway
- Leukotrienes (LT)
- Lipoxins (LX)
List the products of the cyclooxygenase pathway
- Prostacyclins (PGIs)
- Prostaglandins (PGs)
- Thromboxanes (TXs)
Describe the mechanism when a receptor is also an IC enzyme
- Ligand bond formed on the outer surface
- IC polypeptide chain phosphorylates
- Activation of the receptor
- Biological action
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/706/795/a_image_thumb.png?1551784883)
Give an example of direct enzyme stimulation
Insulin receptor
The receptor is able to phosphorylate itself and other proteins on the IC part of the cell
Auto-phosphorylation
- Self phosphorylating enzyme phosphorylates tyrosine residues of the IC receptor sequence
- Phosphorylated tyrosine residues bind intracellular proteins
- Specific IC responses elicited
Describe the processes after autophosphorylation
- Autophosphorylation
- Receptor-enzyme complex is taken up by the cell
- Inactivation
Describe the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/781/169/q_image_thumb.png?1551786120)
- Tyrosine residues are present in the enzyme’s IC domain
- Ligand binding
- Phosphorylation of IC regulatory proteins (RP1+RP2)
- Biological effects
The hypothalamus is divided into which parts?
- Magnocellular area (with large cells)
- Parvocellular area (with small cells)
Describe the movement of hormones from the hypothalamus
- Hormones produced in the parvocellular area → Adenohypophysis
- Hormones produced in the magnocellular area → Neurohypophysis
Which nuclei are found in the magnocellular area?
- Supraoptic nucleus (Oxytocin production)
- Paraventricular nucleus (ADH production)
Which nuclei are found in the parvocellular area?
- Ventromedial nucleus
- Dorsomedial nucleus
- Infundibular nucleus
Inhibit/release substances which can reach the adenohypophysis
Describe the transport of neurosecretions from the parvocellular area
- Parvocellular area
- Portal circulation of pituitary stalk via axons
- Arrive at the adenohypophysis
- Influence production + release of hormones into the blood
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/781/696/a_image_thumb.png?1551786939)
Describe the transport of neurosecretions from the magnocellular area
- Magnocellular area
- From the site of production (Neurone)
- The site of release (Neurohypophysis)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/782/866/a_image_thumb.png?1551787172)
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/787/042/q_image_thumb.png?1551788260)
Axonal transport
Describe the steps of axonal transport
- Peptide travels from hypothalamic cell → axon
- First capillarisation (Median eminence)
- Portal circulation
- Second capilarisation (anterior pituitary)
- Cells of anterior pituitary
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/787/927/a_image_thumb.png?1551788624)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/788/262/q_image_thumb.png?1551788798)
Basal membrane
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/788/458/q_image_thumb.png?1551788826)
Axonal transport, neurosecretion
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/788/484/q_image_thumb.png?1551788877)
First capillarisation (Median eminence)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/788/556/q_image_thumb.png?1551788911)
Portal circulation
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/788/583/q_image_thumb.png?1551788935)
Second capillarisation (anterior pituitary)
Which portal vessel do peptides travel down in axonal transport?
Pituitary stalk
Give the proteins of axonal transport
- Kinesin (Transport from soma to synapse)
- Dynein (Returning of residues to the soma)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/788/762/a_image_thumb.png?1551789476)
In axonal transport, what determines the direction of transport of proteins?
Polarity
Parvocellular areas synthesise releasing and inhibitory substances which influence…
Tropic-hormone production of the adenohypophysis
Hypophyseotrop hormones
Hypothalamic substances that influence production + release of the pituitary gland
Give the parvocellular hormone systematic names
- RH/RF (Releasing hormone/ Releasing factor)
- IH/IF (Inhibiting hormone/ Inhibiting factor)
- ’+’ (Facilitates synthesis + secretion hormones)
- ’-‘ (Inhibits hormone synthesis and release)
E.g TSH-RH = Thyrotropin hormone releasing hormone
In adenohypophyseal systematic naming, what do the following abbreviations mean (Prior to ‘RH’ or ‘RF’)?
- T
- C
- Gn
- G
- P
- M
- T = Thyrotropin, TSH
- C = Corticotropin, ACTH
- Gn = Gonadotropin, FSH/LH
- G = Growth hormone, STH
- P = Prolactin, PRL
- M = Melanocyte stimulating hormone, MSH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/790/785/q_image_thumb.png?1551790918)
- TSH+
- Thyroliberin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/790/939/q_image_thumb.png?1551790975)
- ACTH+
- Corticoliberin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/790/948/q_image_thumb.png?1551791000)
- FSH+, LH+
- Gonadoliberin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/790/962/q_image_thumb.png?1551791029)
- GH+
- Somatoliberin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/790/976/q_image_thumb.png?1551791057)
- PRL+
- VIP, TRH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/791/004/q_image_thumb.png?1551791081)
- MSH+
- MSH-RH
List the releasing factors (short name)
- TRH
- CRF
- GnRH
- GRF
- PRF
- MRF
Function: Thyrotropin-releasing hormone
- Stimulates thyroid gland
- Stimulates hormone release
Function: Corticotropin-Releasing Factor
- Adrenocorticotropin (ACTH) stimulating hormone
- Facilitates synthesis + release of:
- ACTH
- MSH
- Endogenous opiates
- Stimulating + splitting + synthesis of POMC
Function: Gonadotropin-releasing hormone
- Facilitates synthesis + release of:
- FSH (Follicle stimulating hormone)
- LH (Luteinising hormone)
- In males + females
Function: Growth hormone releasing factor (GRF)
Synthesis + release of growth hormone
Function: Prolactin-releasing hormone (PFR)
- Prolactin synthesis + release
- Lactation
- Ovulation in the rat
What are the main parvocellular inhibiting factors?
- Dopamine
- Somatostatin
- GABA
- VIP
In adenohypophyseal systematic naming, what do the following abbreviations mean (Prior to ‘IH’ or ‘IF’)?
- G
- P
- M
- G = Growth hormone, somatotropin, STH
- P = Prolactin, PRL
- M = Melanocyte-stimulating hormone, MSH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/792/653/q_image_thumb.png?1551792763)
- TRH-, PRL-
- TSH-IH, PRL-IH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/792/926/q_image_thumb.png?1551792809)
- GH-
- GH-IH, somatostatin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/792/993/q_image_thumb.png?1551792867)
- PRL-
- PRL-IH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/010/q_image_thumb.png?1551792888)
- GH+
- MSH-IH, Melatostatin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/032/q_image_thumb.png?1551792942)
- General, an indirect inhibitor
- Norepinephrine
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/125/q_image_thumb.png?1551792987)
- General, an indirect inhibitor
Function: GIF
- Systematic name for Somatostatin
- GIF = Growth hormone inhibiting factor
- Somatotropin inhibiting hormone
Function: PIF
- Systematic name for inhibiting factor of prolactin release + production
- Regulated by dopamine
- Hypothalamic peptide is known to decrease prolactin production
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/418/q_image_thumb.png?1551793302)
- PRL+, GIF
- GIF+ In the pancreas
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/597/q_image_thumb.png?1551793365)
- PRL+
- Substance-P antagonist
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/723/q_image_thumb.png?1551793418)
- GH, PRL+
- MSH-IH, melanostatin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/735/q_image_thumb.png?1551793472)
- General facilitator
- Peptide family actin on gastrin
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/758/q_image_thumb.png?1551793498)
- PRL+, GH+, TSH+
- Paracrine action of tachykinins in HP
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/793/778/q_image_thumb.png?1551793542)
- PRL+
The function of: Vasoactive intestinal peptide (VIP)
- PL+
- Somatostatin-
The function of: Angiotensin-II
- Synthesis + release of somatotropin + prolactin
- MSH-inhibiting effect
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/806/406/q_image_thumb.png?1551802609)
- Stimulation of water reabsorption
- Increase BP, V1 receptor, IP3
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/806/587/q_image_thumb.png?1551802651)
- Preparation of uterine contractions for estrogen response, basket cell contraction
- Classical neuroendocrine reflex
Give an example of neuroendocrine reflexes
Oxytocin-mechanisms
What are the essential characteristics of a neuroendocrine reflex?
- Translation of neural information from sensory nerve to the language of the endocrine system (using the hypothalamus)
- Effect/response is not neural but hormonal
Describe the reflexes for milk ejection
- Excitation from udder sensory fibres → Spinal cord
- Excitation → Hypothalamus
- Enhanced oxytocin synthesis evoked
- Oxytocin release increases from the neurohypophysis
- Oxytocin reaches the mammary gland via blood
- Contraction of myoepithelial cells (For milk ejection)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/820/464/a_image_thumb.png?1551809872)
Give the hormonal profile of a cow in stress
- Plasma glucocorticoid level increases, causing:
- Oxytocin fall
- Prolactin fall
- Milk ejection decrease to minimum
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/820/636/a_image_thumb.png?1551809961)
What are glandotropic hormones?
Give examples
Those acting exclusively on endocrine glands
- TSH
- ACTH
- FSH
- LH
What are histiotropic hormones?
Give examples
Those acting on certain organs
- STH
- PRL
The adenohypophysis develops in which structure?
Rathke’s pouch
The adenohypophysis is formed by…tissue
Entodermal glandular
The neurohypophysis is formed by…tissue
Ectodermal nervous
Give the cell types of the hypophysis
- A = Acidophils
- B = Basophils
- C = Chromophobes
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/821/519/q_image_thumb.png?1551810642)
Somatotropin (GH) producing cells
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/821/711/q_image_thumb.png?1551810685)
Adrenocorticotropin (ACTH) producing cells
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/821/772/q_image_thumb.png?1551810719)
Thyrotropin (TSH) producing cells
Prepubertal hypopituitarism/Removal of the pituitary gland
- Results in proportional dwarfism
- In adults:
- Smaller organs
- Thin hairs
- Decreased sexual function
- Decreased protein/glycogen stores
- Decreased BMR
Congenital hyperpituitarism
- Gigantism
- In adult life:
- Acromegaly: Increase in the size of enlargeable extremities and other parts. E.g limbs
Metabotropic hormones of the hypophysis
- GH
- ACTH
- TSH
Gonadotropic hormones of the hypophysis
- PRL
- FSH
- LH
STH/GH receptor mechanism of action
- Hormone binds to the receptor
- IC conformational change
- Activation of the second messenger system
- = G-protein activated cAMP
What direct biological effect does GH have on the body?
- Stimulates somatomedins (further hormones) in the liver
- GH is therefore considered to be glandotropic + histiotropic
Increased growth hormone secretion in young age results in…
Gigantism
Increased growth hormone secretion in adults results in…
Asymmetrical growth of:
- Limbs
- Jaw
- Certain flat bones
Give the episodic release of GH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/269/996/615/a_image_thumb.png?1551959075)
The effect of growth hormone on protein metabolism
- Increases amino acid uptake
- Increases intracellular protein synthesis
- Positive nitrogen balance
The effect of growth hormone on lipid metabolism
- Increases catabolic processes:
- FFA + plasma triglyceride increase
- Fatty deposits are mobilised
- Glucose oxidation decreases
- Gluconeogenesis increases
- Increased plasma acetoacetic acid levels
- Increased plasma beta-OH-butyrate levels
The effect of growth hormone on carbohydrate metabolism
- Antiinsuline effects:
- Decrease insulin-dependent glucose uptake in adipose
- Diabetogenic effects:
- Increase plasma glucose level
- Glucogenesis
- Glucagon production
- Increase plasma glucose level
- Houssay’s experiment
Houssay’s experiment
Adenohypophysectomy improved the status of a diabetic dog
GH stimulates…in the liver
- Activation of thyroid hormones
- Synthesis of somatomedins
Function of somatomedins
- Influence bone, cartilage and connective tissue
- Circulate in plasma, bound by carrier proteins
Somatomedins have a similar structure to…
Insulin
- They are therefore known as IGFs (Insulin-like growth factors)*
- They cannot exert any effect on insulin receptors*
Somatomedins are also known as…
Sulphating factors
IGF =
Somatomedins (Sm)
IGF-I
Sm-C
IGF-II =
MSA
Multiplication stimulating activity
Give the effects of IGF-I
Stimulation of:
- Chondrocyte sulphate intake
- Chondrocyte + osteoblast bone forming activity
- Longitudinal bone growth
- Transversal + periosteal bone growth
- Acromegaly
Rat tibia test
- A biological hormone identification method
- Rat epiphysis’ do not close: always ready to grow
- Unknown substance is administered
- The thickness of the tibial disk is compared with its previous normal size
Describe the regulation of GH secretion
- Plasma levels of:
- Glucose
- Arginine
- Thyroid hormone
- Hypothalamic factors
Peripheral feedback of GH regulation consists of which compounds?
- Plasma metabolites
- IGF
- IGF-BP (Binding protien)
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/090/354/q_image_thumb.png?1552033588)
Regulation of GH secretion
Regulators of GH secretion
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/092/360/q_image_thumb.png?1552033647)
- Plasma glucose + amino acid levels
- Sex
- Stress
- Age
Regulators of GH secretion
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/092/408/q_image_thumb.png?1552033766)
Neurosecretion:
- GH-RH
- GH-IH
Regulators of GH secretion
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/092/413/q_image_thumb.png?1552033862)
Trop. hormone:
- GH
Regulators of GH secretion
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/092/585/q_image_thumb.png?1552033902)
- Metabolites of peripheral tissues + IGF levels
- GH receptors
- IGF binding proteins
Practical approaches of GH
- Increase productivity
- Milk
- Genetic engineering
- rpGH = recombinant-porcine growth hormone
Show the GH effects in cow (Graph)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/092/798/a_image_thumb.png?1552034645)
Biochemical function of ACTH
In the adrenal fasciculate + reticular zones:
- ACTH increases cAMP pathway
- Stimulating glucocorticoid synthesis
What is the primary regulator of aldosterone?
Plasma [K+]
Not ACTH
Many hormones produced in the pituitary gland are synthesised from a common precursor hormone called…
PRE-POMC
- (PRE-PROOPIOMELANOCORTIN)*
- The name is derived from the most important hormones derived from it*
List the hormones derived from Pre-POMC
- Opioid peptides
- MSH
- ACTH
Hormones derived from Pre-POMC are involved in which processes?
Adaptive processes of the body
ACTH is released in the incidence of…
Stress:
- Mobilises energy reserves
- Decreases sensation of pain
Which substance stimulates all the shown cleaving processes?
Where is this substance produced?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/130/037/q_image_thumb.png?1552067670)
CRF (Corticotropin-releasing factor)
Produced in the hypothalamus
LPH =
Lipotropic hormone
CLIP =
Corticotropin like intermediate peptide
Endorphin =
Endogenous morphine
Enkephalin=
Endogenous opioid / Signal peptide
Give the steps of ACTH production
- Pre-POMC
- POMC
- ACTH
Give the effect of ACTH in the glomerulosa layer
Increases cholesterol-pregnenolone conversion →
Increasing mineralocorticoid synthesis
Synthesis of ACTH is regulated according to the…
Classical feedback principle
Long feedback
Involvement of glucocorticoid concentration in ACTH feedback
Ultra-short feedback
The inhibiting effect of ACTH on CRF
Give the steps of neural impulses causing ACTH secretion
- Nerve impulses → Hypothalamus
- Impulses are integrated by CRF synthesising cells
- Circadian fluctuation of CRF
- Determination of ACTH release
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/283/732/q_image_thumb.png?1552234766)
Regulation of ACTH synthesis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/283/842/q_image_thumb.png?1552234960)
Exogenous/endogenous effects
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/070/q_image_thumb.png?1552234989)
- Serotonin
- ACh
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/083/q_image_thumb.png?1552235016)
CRF
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/159/q_image_thumb.png?1552235037)
ACTH
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/171/q_image_thumb.png?1552235074)
Neurosecretion
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/208/q_image_thumb.png?1552235110)
Tropic
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/240/q_image_thumb.png?1552235157)
Steroids
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/273/q_image_thumb.png?1552235199)
- Norepinephrine
- GABA
Circadian rhythm of ACTH
- Short half-life
- Conc. is higher in the early morning
- Lowest at midnight
This is the cause of the fluctuation of glucocorticoid conc. (diurnal rhythm)
Annotate the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/284/559/q_image_thumb.png?1552235457)
- ACTH levels increase in early morning hours
TSH
- Gonadotropic peptide hormone
- Alpha chain: Species specificity
- Beta chain: Biological specificity
What increases TSH levels
- Thyroid hormones
- Hypothalmic TRH
What decreases TSH levels?
- Cortisol
- Dopamine
- Somatostatin
Role of TSH
Stimulation of thyroxine
Plasma TSH concentration is increased by…
TRH
FSH
- Increase oestrogen synthesis in the follicle
- Maturation of the follicle
- Increased testicular spermatogenesis
FSH expression is directed by…
- GnRH
- Steroids
- Inhibin
LH
- Luteinising hormone
- Located: Leydig cell → Testis / Granulosa cell → Ovary
- Increases synthesis of androgens in both organs
- Primary factor initiating ovulation
PRL
Prolactin
- Stimulate mammary gland differentiation
- Stimulate + maintain milk production
- Metabolic hormone
How is PRL stimulated
- Hypothalamic neuronal activity
- Oestrogen inhibits dopamine synthesis
- Stimulating PRL production during ovulation
Give the effects of PRL
- Facilitation of lactogenesis
- Facilitation of galactopoiesis
- Support of suckling
- Ovulation in the rat
Describe the steps toward spontaneous inhibition of PRL
- Spontaneous production of Ca2+ signal in the hypothalamus
- Dopamine synthesis in hypothalamus changes
- Levels of dopamine alter according to a tonic pattern
- Stimulation + suppression of adenohypophyseal PRL production + release
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/286/038/a_image_thumb.png?1552237540)
List the stimuli of PRL production
- Pregnancy
- Suckling
- Stress
- Sleep
- Hypoglycaemia
- Dopamine
List the inhibitors of PRL production
- Dopamine
- GABA
- GAP
- Drug: Bromocryptine
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/287/489/q_image_thumb.png?1552238056)
Positive physiological stimuli and negative effects
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/288/918/q_image_thumb.png?1552238096)
Serotonin opioids
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/190/q_image_thumb.png?1552238126)
Neurosecretion + Peripheral blood-derived signals
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/272/q_image_thumb.png?1552238171)
PRL
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/320/q_image_thumb.png?1552238203)
Trophormone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/362/q_image_thumb.png?1552238234)
Udder:
- Suckling
- Maternal behaviour
Other: Increase of metabolism
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/480/q_image_thumb.png?1552238296)
‘Tonic’ central inhibition
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/551/q_image_thumb.png?1552238331)
- Dopamine
- GABA
- GAP
PRL regulation by neurosecretion involves which hormones?
- TRH
- GnRH
- VIP
- Galanin
PRL regulation by peripheral blood involves which hormones?
- Serotonin
- Angiotensin-II
- Oestrogens
MSH
- Formed from ACTH
- Stimulation of pigment granule production
- Transport along the microtubule system → Decoloration of cells
Effect of MSH on pigment cells
- Microtubule system from the nucleus
- MSH causes:
- Granules to migrate along microtubules
- Even distribution of granules, darkening cell
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/289/937/a_image_thumb.png?1552238818)
Function of melatonin
Hormone:
- Stimulates migration of scattered pigment granules
- Back to the vicinity of the nucleus
Pineal gland produces
Produces serotonin + melatonin
Melatonin secretion
- Circadian rhythm, affected by light
- Decreased illumination acts positively
- Increased daylight acts negatively
Some species:
- Melatonin production positively influences sexual activity
- In other species, it may have a negative influence
Describe the innervation of the pineal gland
- Not directly connected to the CNS
- Innervated by postganglionic sympathetic fibres
Describe the effect of decreased light intensity on the pineal gland
- Decreased illumination to retina → Sympathetic activity
- Suprachiasmatic nucleus (SCN) connection
- Excitation from cervical ganglion → CP
- Norepinephrine released here → NAT synthesis (used in melatonin synthesis)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/314/841/a_image_thumb.png?1552243871)
Title the figure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/315/276/q_image_thumb.png?1552243924)
Innervation of the pineal gland
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/315/491/q_image_thumb.png?1552244040)
Norepinephrine
![](https://s3.amazonaws.com/brainscape-prod/system/cm/270/315/559/q_image_thumb.png?1552244059)
Beta-receptor + Adenylate cyclase