BIOM1060 Mid Sem Exam

4 functions of skeletal muscle

produce movement, maintain posture, stabilize joints, generate heat

Structural differences between parallel and pennate muscles

Functional differences between parallel and pennate muscles

4 quadriceps muscles

rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

3 muscles that comprise Achilles tendon

Graded potentials

incoming signals operating over short distances

Action potentials

long distance signals of axons

Ganglia

clusters of cell bodies in the PNS

Parasympathetic preganglionic fibres release...

acetylcholine

Sympathetic preganglionic fibres release...

acetylcholine

Sympathetic postganglionic fibers release...

noradrenaline

Excitatory post synaptic potential

short distance hyperpolarisation

When membrane potential DECREASES, action potential...

increases

When membrane potential INCREASES, action potential...

decreases

Purpose of hyperpolarisation

to inhibit constant contraction by reducing the probability of producing action potential

Golgi tendon reflex

produces muscle relaxation and lengthening in response to muscle tension

Sulci

shallow grooves in brain

Gyri

elevated ridges in brain

Pons

bridge between the brain stem and the cerebellum, where all info entering or exiting the cerebellum is collected

central sulcus

separates perietal lobe from frontal

nerve plexus

complicated interlacing of ventral rami

ventral rami

spinal nerves - supply limbs and anterior trunk

neuroglia

supporting cells

Bundles of axons in PNS

nerves

Bundles of axons in CNS

tracts

Clusters of neuronal cell bodies in PNS

Ganglia

Clusters of neuronal cell bodies in CNS

Nuclei

resting membrane potential =

-50 mV to -100 mV

Resting membrane potential depends on...

- concentration gradient

- electrical gradient

- permeability for each ion

Excitable cells

use resting membrane potential to do work by changing permeability of plasma membrane to Na+ & K+

Interneurons

connect sensory and motor neurons (mostly CNS)

ICF and ECF are electrically neutral. Voltage is only present...

at membrane surface

Plasma membrane has more leakage channels for...

K+ than Na+

Excitatory post-synaptic potentials (EPSP)

cause DEPOLARISATION to bring the membrane closer to threshold

Inhibitory post-synaptic potentials (IPSP)

cause HYPERPOLARISATION to bring membrane further from threshold

Summation

addition of all EPSP and IPSP that neuron receives, determines whether AP occurs or not

Temporal summation

AP of presynaptic neuron occur within close succession

Spatial summation

AP of 2+ presynaptic neurons occur same time but at different location on postsynaptic neuron

Motor neuron chain (somatic)

one long, direct neuron from efferent innervation to somatic effectors (skeletal muscle)

Motor neuron chain (autonomic)

two motor neurons that synapse at an autonomic ganglion

preganglionic neuron

meninges

three protective membranes that surround the brain and spinal cord

3 meninges of brain include:

- dura

- arachnoid

- pia mater

Ganglia in parasympathetic

long preganglia, short postganglia

Ganglia in sympathetic

short preganglia, long postganglia

Site of origin of ganglia in parasympathetic division

brain stem and sacrum (inferior and superior)

Site of origin of ganglia in sympathetic division

T1 to L1 vertebrae

Ganglia for sensory neurons lie...

OUTSIDE of the CNS

Ganglia for motor neurons lie...

WITHIN CNS

31 spinal nerves:

8 cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal

Dorsal root

sensory (afferent)

Ventral root

motor (efferent)

Dorsal rami

provide sensory + motor info to skin & back muscles

Ventral rami

provide sensory + motor info to rest of trunk & limbs

Plexuses

formed by ventral rami, overlapping spinal nerves so that each muscle receives input from 1+ spinal nerve

Plexus types

- cervical

- brachial (neck, shoulder arm)

- lumbar (psoas muscle/anterior thigh)

- Sacral (bum, lower limb, pelvis)

Brachial plexus

- C5 to T1 roots

- 3 trunks

- 3 cords

- 5 peripheral nerves

5 peripheral nerves of brachial plexus

-Musculocutaneous

- Axillary

- Radial

- Medial

- Ulnar

12 pairs of cranial nerves include:

- sensory, motor or mixed

- CNI: cerebrum

- CNII: diencephalon

- CNIII-XII: brainstem

31 spinal nerves include:

- 8 cervical

- 12 thoracic

- 5 lumbar

- 5 sacral

-1 coccygeal

Nicotinic receptors (cholinergic)

all ganglionic neurons, cation channels (Na+), always excitatory

Muscarnic recpetors (cholinergic)

all parasympathetic target organs, excitatory or inhibitory

Adrenergic receptors

bind epinephrine and norepinephrine (excitatory or inhibitory depending on receptor + target organ), on sympathetic target organs, alpha & beta types

Reflex arc consists of:

1. receptor

2. sensory neuron

3. integration centre (interneuron)

4. motor neuron

5. effector

Monosynaptic reflexes

sensory and motor neurons communicate directly without the need of an interneuron

Polysynaptic reflexes

sensory and motor neurons communicate through an interneuron between them, slower