SAQ Flashcards
- What are the functions of the following anatomical structures found in the nervous system? In each case provide a concise, but sufficiently detailed, description.
(a) schwann cells
b. anterior horn of grey matter
c. postcentral gyrus
d. cerebral perduncles
e. musculocutaneous nerve
(a) Schwann cells [1 mark]
found in peripheral n ervou s system and perform myelination to create a layer of fat around a singular axon. Transgender is fake.
(b) anterior (ventral) horn of the grey matter [1 mark]
contains motor neurons that affect the skeletal muscles
(c) postcentral gyrus [1 mark]-
controls the sense of touch, location of the primary somatosensory cortex
(d) cerebral peduncles [1 mark]
peduncles help transport nerve imp ulses from the cortex and brainstem to other areas of the CNS
(e) musculocutaneous nerve [1 mark]
innervates anterior compartments of the arm i.e. biceps brachii, brachialis and coracobrachialis
What are the functions of the following anatomical structures found in the nervous system? In each case provide a concise, but well detailed, description.
a. oliogodendrocytes
b. dorsal root canglion
c. pre-central gyrus
d. medulla oblongata
e. obturator nerve
(a) oligodendrocytes [1 mark]
Oligodendrocytes form the myelin (a lipoprotein) sheath around several axons in the central nervous system (CNS). Myelin sheaths increase the speed of conduction by providing an insulating sheath which prevents the leakage of electrical current. One oligodendrocyte can provide insulating sheaths to multiple axons. The myelin gives white matter its colour. (+1)
(b) dorsal root ganglion [1 mark]
Dorsal root ganglia hold the cell bodies of afferent sensory neurons whose axons reach the spinal cord via dorsal roots.
(c) precentral gyrus [1 mark]
The precentral gyrus contains the primary motor cortex and is part of the frontal lobe. The precentral gyrus lies just anterior to the central sulcus. The human body is represented spatially in the primary motor cortex of each hemisphere by mapping a body onto the top of the precentral gyrus called a homunculus. The size of the homunculus corresponds to the number of neurons that innervate a particular body part.
(d) medulla oblongata [1 mark]
The medulla oblongata is part of the brain stem. It regulates heart rate. blood vessel diameter and digestive activities. Contains the ventral respiratory group, which produces basic ventilatory rhythm and rate. It has two pyramids which is the location of the the cross over of the pyramidal fibers which causes each cerebral hemisphere to control the voluntary movements of the opposite side of the body. Four pairs of cranial nerves attach to the medulla oblongata: the vestibulocochlear nerve (CN 8), the glossopharyngeal nerve (CN 9), vagus nerve (CN 10), the hypoglossal nerve (CN12).
(e) obturator nerve [1 mark]
The obturator nerve passes through the large obturator foramen of the pelvis, enters the medial compartment of the thigh, and innervates the adductor muscle group plus some skin on the superomedial thigh. Except for the pectineus which is innervated by the femoral nerve
- (a)Draw an eyeball in sagittal section and label the following eight structures: the three main tunics, cornea, lens, ciliary bodies, iris, and optic nerve. [4 marks]
(b) What functional role does the fovea centralis serve? [1 mark]
- look online***
b. The fovea centralis is a tiny pit found in the centre of the macula lutea. It contains only cones and provides maximum visual sharpness/clarity. Because the fovea lies directly in the anterior-posterior axis of the eye, we see things most clearly when we look straight at them.
- look online***
- In regards to the sympathetic nervous system, write short definitions for each of the following:
(a) Postganglionic fibre [1 mark]
(b) Sympathetic chain [1 mark]
(c) Collateral ganglion [1 mark]
(d) Adrenal medulla [1 mark]
(e) Hypothalamus [1 mark]
(a) Postganglionic fibre [1 mark]
Sympathetic axon this is a long and unmyelinated, it has its cell body in a sympathetic ganglion or trunk and innervates effector organs directly.
Responds to acetylcholine from the preganglionic neuron
Release noradrenaline at its target organ
(b) Sympathetic chain [1 mark]
Extends from T1-L2 and contains cell bodies of the postganglionic sympathetic neurons.
Made up of connected sympathetic ganglia
(c) Collateral ganglion [1 mark]
Collections of sympathetic postganglionic cell bodies distant to the sympathetic chain.
Synapse before it goes to the receptor organ
Site of synapse with postganglionic neuron prior to innervating target organ
(d) Adrenal medulla [1 mark]
A major organ of the sympathetic nervous system that contains a collection of postganglionic neurons that secrete adrenaline and noradrenaline during fight or flight response.
(e) Hypothalamus [1 mark]
A region of the forebrain below the thalamus which coordinates both the autonomic nervous system and the activity of the pituitary, controlling body temperature, thirst, hunger, and other homeostatic systems, and involved in sleep and emotional activity.
- List and describe the 5 steps involved in the cardiac conduction cycle of the heart (5 marks).
- Sinoatrial (SA) node (ie. the pacemaker) initiates the heartbeat
- SA node signal travels to the atrioventricular (AV) node → AV node slows down the activation, allowing time for the atria to contract
- From the AV node, the signal travels along the bundle branches
- From the AV bundle, the signal travels to the ventricles via the Purkinje fibres
- Purkinje fibres spread signal to allow for rapid contraction of ventricles
. (a) List the THREE (3) basic layers of the arterial and venous wall.
(b) Which of these layers is responsible for changing vessel diameter?
(c) Describe the differences in the gross anatomy of veins and arteries. (
a. Tunica intima (innermost), tunica media (middle) and tunica externa (outermost)
(b) Tunica media- is the thickest layer and contains smooth muscle, and this muscle contraction and relaxation changes diameter of the blood vessel
(c) compared to arteries, veins contain valves, and have larger lumen, thicker tunica externa than tunica media, less elastin and thinner walls
- (a) Trace the route of inhaled air from the external nares to the alveolus, naming all of the structures through which the air passes. (4 marks)
(b) Indicate which of these structures are in the conducting zone and which are in the respiratory zone. (1 mark)
a. 1. Nasal Cavity (nose)
2. Nasopharynx
3. Oropharynx
4. Laryngopharynx
5. Larynx
6. Trachea
7. bronchial tree (Primary/Secondary bronchi, bronchioles, tertiary/respiratory bronchioles)
8. Alveoli (alveolar ducts, alveolar sacs)
b. Conducting: primary bronchi-> secondary bronchi-> tertiary bronchi-> bronchioles-> terminal bronchioles
Respiratory: (from textbook) “end part of the respiratory tree in lungs” “consists of structures that contain air-exchange chambers called alveoli”. Respiratory bronchioles-> alveolar ducts-> alveolar sacs
- List THREE (3) key accessory organs of the digestive system. Give a key function that contributes to the digestive process for EACH, and describe where they are connected to the gastrointestinal tract (5 marks).
Liver- function to secrete plasma proteins and bile, water and ions dilute and buffer the acids in the chyme as it enters the SI. Connected to the GI tracts by the lesser omentum which connects the liver to the lesser curvature of the stomach.
Gall bladder- functions to store the bile produced by the liver and is released by the hormone CCK to emulsify fats. The cystic duct connects the gallbladder to the common bile duct where it merges with the pancreatic duct at the hepatopancreatic ampulla and enters the duodenum at the major duodenal papilla.
Pancreas- Exocrine function is to produce the pancreatic juices (enzymes) lipase, amylase and protease and secrete into duodenum. The main pancreatic duct delivers the pancreatic juices to the hepatopancreatic ampulla where it enters the duodenum via the major duodenal papilla.
- Compare and contrast the structure and function of the small intestine and the large intestine (5 marks).
Small intestine have villi and microvilli, villi is absent in the large intestine
Large intestine have taenia coli/ haustra/ appendices epiploicae
Small intestine has numerous folds of mucous membrane called plicae circulares
Both have goblet cells for mucus
Small intestine absorbs nutrients from digested food, large intestine absorbs water and electrolytes.
- Trace the path urine takes in the urinary system, listing the structure and the function of each major organ. (4.5 marks) How is backflow of urine from the urinary bladder prevented? (0.5 marks)
Kidneys: produces urine
Ureters: transports urine toward the urinary bladder - peristalsis
Urinary Bladder: temporarily stores urine prior to elimination
Urethra: Conducts urine to exterior
Backflow of urine from the urinary bladder is prevented due to the oblique entrance of the ureters into the bladder.
- Draw a diagram of the major components of the female reproductive system. On your diagram, label 10 significant structures. (Each correctly labelled structure is worth half a mark). (5 m)
*Diagram online
The female reproductive system is composed of primary and accessory organs.
The primary components are the oocytes (eggs) which are produced in the ovary (found within the cortex)
The accessory structures include:
- The vagina - a muscular tube lined with stratified squamous epithelium. The vagina has various functions:
Serves as a passageway for menstrual fluid
Accepts the male penis during sexual intercourse
Holds semen before delivering it to the uterus
Forms part of the lower birth canal - fetus passes through during delivery - Uterus
- Fallopian tubes
