Week 12 - How does it all work? Flashcards
Where does the spinal cord come from?
foramen magnum to the first or second lumbar vertebrae
How many pairs of spinal nerves are there?
31
What are the regions of the spinal cord?
cervical, thoracic, lumbar, sacral, coccygeal
Where are the enlargements of the spinal cord?
cervical and lumbosacral regions –> arms and legs
What is the cauda equina?
branches from the L5 enlargement
What are the meninges
connective tissue covering the spinal cord and brains
What are the functions of the meninges?
- protect CNS and blood vessels
- contains CSF
- forms partitions in the skull
Describe the three meningeal layers in the spinal cord?
Dura mater
-contains subdural space –> serous fluid
Arachnoid mater
-contains subarachnoid space –> cerebrospinal fluid and blood vessels
Pia mater
-many small blood vessels
Where are sensory and motor neurons found?
sensory: dorsal roots
motor: ventral roots
What is the structure of a nerve?
- endoneurium - surrounds axon and associated schwann cells
- perineurium - surrounds a group of axons or a nerve fascicle
- epineurium - surrounds a group of fascicles
How many cervical, thoracic, lumbar, sacral and coccygeal nerves are there?
Cervical: 8 pairs Thoracic: 12 pairs Lumbar: 5 pairs Sacral: 5 pairs Coccygeal: 1 pair
What are the parts of the brain?
- forebrain –> cerebrum, diencephalon
- midbrain
- hindbrain –> pons, medulla oblongata, cerebellum
Which parts form the branistem?
midbrain, hindbrain (pons, medulla oblongata)
Medulla oblongata
- autonomic reflex centre
- cardiovascular centre - regulates heart rate, force of contractions, blood vessel diameter
- respiratory centre - regulates rate and depth of breathing
- other reflexes - swallowing, vomiting, hiccuping, coughing, sneezing
Pons
- contains conduction tracts: longitudinal (spinal cord –> higher brain centres; transverse tracts (cerebrum and cerebellum)
- sleep centre (REM)
- respiratory centre (works with medulla oblongata)
Midbrain
- receives visual, auditory and tactile sensory output
- generates reflex movements of head, eyes, body
- controls movement of the eye
cerebellum
-controls locomotion, in association with cerebrum
-fine motor control
posture and balance
What does the diencephalon consist of?
- thalamus
- subthalamus
- epithalamus
- hypothalamus
What are gyri, fissures and sulci?
Gyri: elevated tissue or folds
Sulci: groove
Fissures: deep grooves
What are longitudinal fissures?
separates left and right hemispheres
What is the lateral fissure?
separates temporal lobe from the rest of the cerebrum
Precentral gyrus?
primary somatic motor cortex
Postcentral gyrus?
primary somatic sensory cortex (primary somatosensory cortex)
Frontal lobe?
voluntary motor function, motivation, planning, aggression, sense of smell, regulation of emotional behaviour and mood
Parietal lobe?
area which receives the most sensory input except for smell, hearing, taste and vision
Occipital lobe?
receives and processes visual input
Temporal lobe?
receives and processes smell and hearing, role in memory
What are the lobes of the cerebrum?
frontal, parietal, occipital, temportal
What is the function of the corpus callosum?
connects two vertebral hemispheres together
What is the role of limbic system?
role in memory, development of neuropathways
Describe the meningeal layers of the brain?
Dura mater -periosteal dura dural venous sinus: venous blood, dural folds -meningeal dura -subdural space: serous fluid Arachnoid mater -subarachnoid space: CSF and blood vessels Pia mater -many small blood vessels
What are the functions of ventricles?
- production of CSF
- lined with ependymal cells
Cerebrospinal fluid
- produced in choroid plexus
- protects brain and spinal cord from trauma
- provides buoyancy
- similar composition to blood plasma but less proteins and different ionic concentrations
How many cranial nerves are there?
12, named after Roman numerals
Division of sympathetic division?
thoracolumbar
Division of the parasympathetic division?
craniosacral
Autocrine
local effect on the same cell type from which the chemical signals are released
Paracrine
affect other cell types locally without being transported in the blood
Neurotransmitter
produced by neurons, secreted into extracellular space
Endocrine
produced by cells of endocrine glands, enters circulatory system and affects distance cells
Characteristics of hormones
- produced in small quantities
- transported some distance in the circulatory system
- acts of target tissue elsewhere in the body
Types of hormone secretion
- acute: sudden release duer to stimulus
- chronic: small variations over long periods
- episodic: estrogen and progesterone
What are some functions of the endocrine system?
metabolism, control of food intake and digestion, tissue maturation, ion regulation, water balance, HR and BP regulation, control of blood glucose and other nutrients, controls reproductive functions, uterine contraction and milk release, immune system regulation
Difference between posterior and anterior pituitary
- posterior: nervous tissue
anterior: endocrine tissue
Describe the relationship between the anterior pituitary and hypothalamus
-releasing and inhibiting factors produced by the hypothalamus pass to anterior pituitary, causing it to release hormones
What are the hormones of the anterior pituitary?
Growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, melanocyte-stimulating hormone, luitenizing hormone, prolactin
Describe the relationship between the posterior pituitary and hypothalamus
-nervous stimulation of cells of posterior pituitary cause the posterior pituitary to release hormones
What are the hormones of the posterior pituitary?
ADH, oxytocin
Give an example of negative feedback
T3 and T4 from thyroid gland, when enough is in the blood stream, the thyroid stops producing it until it is needed again
Give an example of positive feedback
oxytocin during childbirth, uterine contractions cause the release of oxytocin
