BIOL 320 Lab Practical 1

Layers of veins/arteries

1. Tunica externa: connective tissue

2. Tunica media: smooth muscle in both, elastic fibers in arteries

3. Tunica intima: connective tissue and endothelium

Types of arteries

1, Elastic/conducting: large, close to the heart; high amounts of elastic fibers

2, Muscular/distributing arteries: further from heart, more smooth muscle

What 3 arteries receive blood from the aortic arch?

1. Brachiocephalic artery/trunk

   1. divides into right common cartoid artery and right subclavian artery

2. Left common carotid artery: blood → left side of head

3. Left subclavian artery: blood → left upper limb

Two components of the descending aorta

1. Thoracic aorta: above the diaphragm, turns into intercostal arteries

2. Abdominal aorta: below the diaphragm

Which arteries take blood to the brain?

Vertebral arteries and common carotid arteries

Functions of the left and right subclavian arteries

Each has one branch that takes blood to the brain and one that becomes the left axillary artery and axillary artery, respectively

How do the subclavian arteries take blood to the brain?

Subclavian arteries → Vertebral arteries → Travel through transverse foramina of cervical vertebrae → Foramen magnum → Basilar artery @ base of brain → cerebral arterial circle

Functions of common carotid arteries

Each one branches below mandible to form external carotid artery (takes blood to face) and internal carotid artery (takes blood to brain)

How do the carotid arteries take blood to the brain?

Carotid canal → blood to base of brain → cerebral arterial circle

Cerebral arterial circle/circle of Willis

Vessel containing the combined blood from the basilar and carotid arteries; forms a loop around pituitary gland.

Composed of anterior and posterior communicating arteries.

Collateral circulation

The reuniting of arteries; ensures that even if one artery becomes congested, the brain still receives blood supply

Cerebral arteries

Arteries that branch off of cerebral arterial circle and take blood directly to the brain; anterior, middle, posterior cerebral arteries

Branches of the descending aorta

1. Celiac trunk/artery

   1. Splenic artery: spleen & pancreas

   2. Left gastric artery: stomach & esophagus

   3. Common hepatic artery: liver

2. Superior mesenteric artery: small intestine, proximal large intestine

3. Suprarenal arteries: adrenals

4. Left & right renal: kidneys

5. Gonadal: testes/ovaries

6. Inferior mesenteric artery: lower portion of large intestine

What two arteries does the abdominal aorta divide into?

1. Internal iliac artery: pelvic region

2. External iliac artery

What do the external iliac arteries turn into?

Exit through inguinal canal and continue into thigh as femoral artery

Arteriosclerosis

Hardening of the arteries caused by the development of cholesterol plaque

Where does blood leaving the brain flow into?

Internal jugular veins

Irritability

the potential of a nerve to respond to a stimulus

Conductivity

movement of a nerve impulse along the length of a neuron

Which brain waves are active during waking hours?

Alpha and Beta

Which brain waves are active during sleeping hours?

Theta and Delta

Threshold voltage

Minimum voltage required for nerve conduction

Maximum recruitment voltage

Voltage that causes maximum contraction of a muscle

List the steps of the reflex arc

Receptor → Afferent neuron → Integration center → Efferent neuron → Effector

Somatic reflex

The effector is a skeletal muscle

Visceral reflex

The effector is smooth or cardiac muscle

Polysynaptic reflex arc

Involves synapses between many neurons

Monosynaptic reflex arc + example

Involves a synapse between only two neurons; e.g. the patellar reflex

Meissner corpuscle

Detects light pressure, located in the upper dermis

Merkel disc

Detects light touch, located in lower epidermis

Pacinian corpuscle

Detects deep pressure, located in deep dermis

What happens when skin temperature exceeds the perception of thermoreceptors?

Nociceptors are activated

Name all the types of receptors

1. Mechano (touch)

2. Chemo (chemical)

3. Photo (light)

4. Baro (pressure)

5. Noci (pain)

6. Proprio (tension)

Sclera

White of the eye, covered by conjunctiva. Serves as an attachment point for muscles and helps maintain intraocular pressure.

What parts of the eye make up the fibrous tunic?

The sclera and cornea (continuous with one another)

Lateral rectus

Innervation: Abducens VI

Turn direction: Laterally

Medial rectus

Innervation: Oculomotor III

Turn direction: medially

Superior rectus

Innervation: Oculomotor III

Turn direction: superiorly

Inferior rectus

Innervation: Oculomotor III

Turn direction: inferiorly

Inferior oblique

Innervation: Oculomotor III

Turn direction: superiorly and laterally

Superior oblique

Innervation: Trochlear IV

Turn direction: inferiorly and laterally

Lacrimal apparatus contents and purpose

1. Lacrimal gland: secretes tears

2. Nasolacrimal duct: conducts tears to nasal cavity

Cornea

Bends light rays to allow for focus of images

What are the anterior and posterior chambers of the eye filled with?

Aqueous humor

Sphincter pupillae

Constrict in bright light, reduce pupil size

Dilator pupillae

Dilate in low light, increase pupil size

What body creates aqueous humor?

Ciliary body

What is the vitreous chamber filled with?

Vitreous humor that helps maintain the shape of the eyeball

What are the 3 tunics of the vitreous chamber?

1. Fibrous tunic: sclera + cornea

2. Vascular tunic: ciliary body + iris

3. Nervous tunic: retina

List the steps of light transmission

Light strikes photoreceptors in posterior retina → ganglion cells → optic nerve

What are the 3 layers of the retina?

1. Ganglionic

2. Bipolar

3. Photoreceptive

Location and function of rods and cones

Located in the photoreceptive layer of the retina

Rods: perceive shapes and dim light

Cones: perceive color and detail

What is the fovea centralis?

The area of the retina with the greatest concentration of cones; used for intense focus

Near point

Minimum distance an object can be held in focus; determined by the elasticity of the lens

Binocular/stereoscopic vision

Allows for depth perception

Astigmatism

Curving of the lens causes light to look blurred

What structures does the external ear consist of?

Auricle/pinna (helix + earlobe), external acoustic meatus, tympanic membrane (eardrum)

What structures does the middle ear consist of?

Tympanic cavity (3 ossicles), eustachian tube

What 3 bones comprise the ossicles?

Malleus, incus, stapes

What are the 3 regions of the inner ear?

Cochlea, vestibule, semicircular canals

What are the functions of the cochlea?

Hearing; vibrations cause fluid to move in and out of oval window and round window

Which region of the cochlea would a 20,000 Hz sound stimulate? What does this mechanism allow for?

Region closest to the middle ear; allows cochlea to perceive multiple sounds at different pitches at once

What is the structure and function of the vestibule?

Static labyrinth - interprets static balance and acceleration

What is the structure and function of the semicircular canals?

Dynamic labyrinth - interpret moving/dynamic balance

1. Anterior semicircular canals: motion in the forward plane

2. Posterior semicircular canals: sideways motion

3. Lateral semicircular canals: circular motion

Conduction deafness

Mechanical issue with the outer or middle ear where vibrations do not reach the cochlea

Sensorineural hearing loss

Issue in the cochlea, vestibulocochlear nerve, or auditory center of temporal lobe

What does plasma consist of?

91% water, rest is salts, vitamins, wastes, proteins (albumins, globulins, fibrinogens)

Name all types of WBC

Granulocytes

• Neutrophils (acute bacterial infections)

• Eosinophils (allergic reactions, parasitic infections)

• Basophils (allergic and inflammatory reactions)

Agranulocytes

• Lymphocytes (bacterial infections)

• Monocytes (chronic infections)

Mediastinum

Region that contains the heart

Layers of the outer heart

1. Fibrous pericardium

2. Serous pericardium

   1. parietal pericardium

   2. pericardial cavity

   3. epicardium

Layers of the inner heart wall

1. Epicardium - epithelial & connective tissue

2. Myocardium - thickest, cardiac muscle

3. Endocardium: endothelium & connective tissue

Why is the left ventricle wall thicker than the right ventricle wall?

The right ventricle only has to generate enough pressure to pump blood to the lungs, while the left ventricle has to pump blood to all body systems

Interventricular sulcus

Separates the left and right ventricles (on surface)

Atrioventricular sulcus

Junction of right atrium and right ventricle

Coronary sinus

large chamber that carries blood from cardiac veins to the right atrium

Interventricular septum

Forms a wall between two ventricles

Interartrial septum

Medial wall of the atrium ; contains fossa ovalis/foramen ovale (in fetus)

Chordae tendinae

Threadlike attachments on tricuspid valve that attach to papillary muscles

Trabeculae carnae

Strengthen right ventricle wall

What is the purpose of valves?

Prevention of backflow

What do systole and diastole correspond with?

Systole = contraction

Diastole = relaxation

Where do electrical impulses of the heart begin?

sinoatrial node

What do depolarization and repolarization correspond with?

Depolarization = contraction

Repolarization = relaxation