1 - CNS + Endocrine System Flashcards
What are the major parts of the brain?
Cerebrum
Cerebellum
Brainstem
What are the main lobes of the cerebrum?
Frontal: voluntary motor function, sense of smell, aggression
Parietal: Receive and evaluate sensory information (excluding: smell, hearing, taste + vision)
Occipital: Receive and integrate visual input
Temporal: Receives and evaluates input for smell and hearing + important role in memory
What are the main sulci of the cerebrum?
Sulci: divide each hemisphere into lobes
Longitudinal fissure: separates the left and right hemispheres
Central sulcus: separates frontal and parietal lobes
Lateral sulcus: separates frontal + parietal lobes from temporal lobe
What are the main gyri of the cerebrum?
Precentral gyrus: primary motor cortex
Postcentral gyrus: primary somatic sensory cortex
What advantage do the convolutions giver the cerebrum?
Increases surface area to allow for more neurons to process and receive information
What are the three parts of the brainstem?
- Medulla Oblongata
- Pons
- Midbrain
What is the role of the medulla oblongata?
Regulation
- Heart rates, coughing + sneezing, blood vessel diameter
What is the role of the pons?
- Sleep centre
- Respiration
- Posture
What is the role of the mid brain?
- Visual: Coordinate head + eye movements
- Auditory: Startle reflex
What are the components of reflex arc?
- Sensory receptor
- Sensory neuron
- Interneuron
- Motor neuron
- Effector organ
Differences between somatic and autonomic reflex (Effector)
Somatic:
- skeletal muscle
Autonomic:
- Smooth muscles, cardiac muscle, body organs
Differences between somatic and autonomic reflex (Regulator)
Somatic:
- Controls all conscious + unconscious movements
Autonomic:
- Unconscious regulation
Differences between somatic and autonomic reflex (Response to stimulation)
Somatic:
- Contraction of muscles
Autonomic:
- Inhibition or stimulation of muscles
Differences between somatic and autonomic reflex (Neuron Arrangement)
Somatic:
- One neuron
Autonomic:
- Preganglionic: CNS -> autonomic ganglion
- Postganglionic: autonomic ganglion -> target tissue
Differences between somatic and autonomic reflex (Location of neuron)
Somatic: - Motor nuclei of cranial nerves - Ventral horn of spinal cord Autonomic: - Preganglionic: autonomic nuclei of cranial nerves + lateral part of spinal cord - Postganglionic: autonomic ganglia
Differences between somatic and autonomic reflex (No# of synapses)
Somatic:
- 1 synapse (between motor neuron + skeletal muscle)
Autonomic:
- 2 synapses (autonomic ganglia + target tissue)
Differences between somatic and autonomic reflex (Myelination)
Somatic: - Myelinated Autonomic: - Preganglionic: myelinated - Postganglionic: unmyelinated
Differences between somatic and autonomic reflex (Neurotransmitter)
Somatic: - Acetylcholine Autonomic: - Preganglionic: acetylcholine - Postganglionic: acetylcholine, adrenaline/noradrenaline
Differences between somatic and autonomic reflex (Receptor molecule)
Somatic:
- Nicotonic
Autonomic:
- Autonomic ganglia: for acetylcholine are nicotinic
- Target tissue: for acetylcholine muscarinic
- For adrenaline: a- or b-adrenergic
Describe the function of the hypothalamus
- Controls endocrine system, the infundibulum connects hypothalamus to pituitary gland.
1. Regulation
Food intake
Water + thirst
Cardiac + smooth muscle
Body temperature
Sleep + wake cycles
Endocrine function
What are the differences between anterior and posterior gland (Embryological derivation)
Anterior: epithelia tissue in roof of mouth
Posterior: outgrowth of inferior part of brain in hypothalamus, infundibulum enlarges to form PP.
What type of connection exists between anterior pituitary and hypothalamus?
- Vascular
- Hypothalamo-hypophysical portal system
What type of connection exists between posterior pituitary and hypothalamus?
- Neural
- Hypothalamo-hypophysical tract
What is the relationship between the anterior pituitary and hypothalamus?
- Hypothalamus secretes releasing + inhibiting hormones
1. Stimuli within NS regulate secretion of releasing + inhibiting hormones from neurons in hypothalamus
2. Releasing and inhibiting hormones pass through hypothalamopophysial portal to anterior
3. Releasing and inhibiting hormones leave capillaries to stimulate/inhibit release of hormones
What is the relationship between the posterior pituitary and hypothalamus?
- Hypothalamus creates ADH and oxytocin to be released from posterior pituitary
1. Stimuli within NS cause hypothalamic neurons to increase or decrease AP frequency
2. AP conducted by axons through hypothalamohypophysial tract to posterior
3. In posterior, AP cause release of neurohormones from axon terminals into blood
What hormones are released from the posterior pituitary?
- Oxytocin:
2. Anti-Diuretic hormone:
Oxytocin hormone
- Posterior pituitary
- Amino acid derived, water soluble (indirect)
- Acts on uterus + mammary glands
- Uterus contractions during birth
- Begins production of milk
Anti-Direutic Hormone
- Posterior pituitary
- Peptide hormone, water soluble (Indirect)
- Acts on kidneys
- Water retention
Lutensing Hormone
- Anterior Pituitary
- Protein hormone, water soluble (Indirect)
- Acts on gonads
- Testis: sperm production
- Ovary: Ovulation
Follicle Stimulating Hormone
- Anterior pituitary
- Protein hormone, water soluble (Indirect)
- Acts on gonads
- Testis: sperm production
- Ovary: Growth of ovarian follicle
Thyroid Stimulating Hormone
- Anterior pituitary
- Protein, water soluble (indirect)
- Acts on thyroid gland
- Stimulates production of thyroixine (t4) and triidothyronine (t3)
Growth hormone
- Anterior pituitary
- Protein, water soluble (indirect)
- Acts on most body tissues
- Growth of tissues and bones
Adrenocorticotropic Hormone
- Anterior pituitary
- Protein, water soluble (indirect)
- Acts on adrenal cortex
- Stimulate secretion of cortisol + androgens
Aldosterone
- Adrenal cortex
- Steroid, lipid soluble (direct)
- Water reabsorption with sodium
- Regulating blood pressure
Cortisol
- Adrenal cortex
- Steroid, lipid soluble (direct)
- Acts on many organs
- Control sugar levels and regulate metabolism
Adrenaline/Noadrenaline
- Adrenal medulla
- Amino acid derived, water soluble (indirect)
- Fight or flight (increased bp)
- Rest or digest (decreased bp)
T3/T4
- Thyroid
- Amino acid derived, water soluble (direct)
- Regulate metabolism, body temp. + heart rate
Calcitonin
- Thyroid
- Peptide, water soluble (indirect)
- Regulate calcium levels
Parathyroid hormone
- Parathyroid gland
- Peptide, water soluble (indirect)
- Acts on bones
- Raise calcium levels in blood
Glucagon
- Pancreas
- Peptide, water soluble (indirect)
- Acts on liver
- Prevent low blood glucose levels
- Glycogenolysis: conversion of glycogen to glucose
Insulin
- Pancreas
- Protein, water soluble (water soluble)
- Acts on liver
- Stimulates uptake of glucose from the blood
What parts is the thyroid composed of?
Right lobe, left lobe, isthmus
What are the 3 zones of the adrenal cortex?
zona glomerulosa
zona fasciculata
zona reticularis
What are the exocrine and endocrine components of the pancreas?
exocrine: secretes pancreatic juice for digestion, uses a duct for transport
endocrine: consists of islets (ductless) secrete products into cardiovascular system
What are the 3 main types of cells found in Islets of Langerhans?
- Alpha cells: secrete glucagon
- Beta cells: secrete insulin
- Delta cells: produce somatostatin
Distinguish between endocrine and exocrine glands
Endocrine - Chemical messenger: hormones - Secreted into bloodstream Exocrine - Ducts carry secretions to external openings
Define tropic hormone
Hormones that stimulate the release of other hormones
Distinguish between lipid and water soluble
Lipid soluble: - non polar - bind to receptors in the nucleus - able to diffuse through plasma membrane Water soluble: - polar - attach to receptors on plasma membrane - unable to diffuse through plasma membrane
Method of action: Direct
Lipid soluble hormones
- Travels in the blood attached to a binding protein
- released from its binding protein in the blood
- diffuses out of capillary into interstitial fluid
- diffuses through the plasma membrane of its target cell
- lipid s. hormone binds to cytoplasmic receptor
- Receptor/hormone complex travels to the nucleus
- Receptor/hormone complex binds to the DNA
- Activates production of mRMA molecules
- mRNA moves to the cytoplasm to be translated into specific peptide/polypeptides and proteins
Method of action: Indirect
- Water soluble hormones
1. travels in the blood as a free hormone
2. diffuses out of the capillary into the interstitial fluid
3. Hormone attaches to a receptor on the surface of the target cell plasma membrane
4. Receptor/hormone complex activates G-proteins located just beneath surface of cell membrane
5. G-proteins alter activity of an enzyme - Adenyl-Cyclase
6. ATP enzymically converted to cyclic AMP (cAMP) - acts as a second messenger
7. Protein-kinases (regulatory enzymes) are activated by cAMP
8. Various cell processes are altered by protein kinases
Negative feedback
- Depends on levels of hormone present in the blood
- In excess: hormone secretion is inhibited
- In deficit: hormone secretion is stimulated
Positive Feedback
- Reinforce secretion of hormone, stimulated by tropic hormone
Define autocrine + example
- Secreted by cells in local area
- Influences activity of same cell from which it was secreted
e. g eicosanoids
Define paracrine + example
- Produced by many tissues
- Secreted into ECF
e. g histamine, somatostatin
What are the three meninges layers?
- Dura mater
- Arachnoid mater
- Pia mater
Describe the dura mater
- Superficial, thickest layer
- Epidural space: separating the dura mater from peritoneum + vertebral canal
- Contains: spinal nerves, blood vessels
Describe the arachnoid mater
- Middle layer, thin + wispy
- Subdural space contains serous fluid
Describe the pia mater
- Innermost layer, bound to spinal cord surface
- Subararachnoid space: between pia + arachnoid
contains BVs + CSF
