Text Questions Flashcards
1
Q
How many pairs of cranial nerves?
A
12
2
Q
How many pairs of spinal nerves?
A
31
3
Q
What is the forebrain called? What is it composed of?
A
Prosencephalon
- Cerebrum
- Diencephalon
4
Q
What is the midbrain called?
A
Mesencephalon
5
Q
What is the hindbrain called? What is it composed of?
A
Rhombencephalon
-Medulla oblongata
Pons
Cerebellum
6
Q
What is tectum?
A
Visual and auditory processing
7
Q
What is the reflex to visual stimuli in the midbrain via?
A
The superior colliculus
8
Q
What is the reflex to auditory stimuli in the midbrain via?
A
The inferior colliculus
9
Q
What is tegmentum?
A
Subconscious control of upper limb position and muscle tone
10
Q
What is the pons?
A
The bridge linking the cerebellum with the mesencephalon, diencephalon, cerebrum and spinal cord
11
Q
What nuclei of cranial nerves are on the pons?
A
V, VI, VII and VIII
12
Q
What cell does myelination in the PNS?
A
Schwann cells
13
Q
Are unmyelinated axons still encased by Schwann cells?
A
Yes, but only a single cell membrane layer
14
Q
What is a dermatome?
A
The area of skin innervated by a single spinal nerve
15
Q
How do dermatomes spiral down the limb during foetal development?
A
The dramatic medial rotation of the lower limbs during the 6th to 8th week causes the mature dermatomes to spiral down the limb.
16
Q
What is the space located between the sternum, spine, lungs and diaphragm?
A
The mediastinum
17
Q
How many layers of pericardium?
A
Three
18
Q
Two main types of pericardium?
A
Fibrous and serous
19
Q
Two types of serous pericardium?
A
Parietal layer - outer Visceral layer (epicardium)
20
Q
What is the fluid between the two layers of the pericardium called?
A
The pericardial cavity
21
Q
Three layers of the heart? Which one is the contractile layer?
A
Epicardium
Myocardium - contractile
Endocardium (deep)
22
Q
What is the endocardium of the heart comprised of?
A
Sheet of simple squamous epithelium on a thin layer of connective tissue (lines chambers and valves)
23
Q
What are cardiac cells interconnected at? What type of junctions are they?
A
Junctions called intercalated discs
- Gap junctions
- Desmosomes
24
Q
What are atria of the heart separated by?
A
The inter-atrial septa
25
What are ventricles of the heart separated by?
The inter-ventricular septa
26
What type of tissue is the septa's' of the heart?
Fibrous
27
What are the valves of the heart attached to?
Chordae Tendineae
28
Three main vessels the right atrium receives from?
Super vena cava, inferior vena cava and the coronary sinus
29
What is the enclosed hole between the two artias?
Fossa ovalis
30
What are pectinate muscles?
The pectinate muscles (musculi pectinati) are parallel ridges in the walls of the atria of the heart. They are so-called because of their resemblance to the teeth of a comb as in pecten.
31
What layer of heart tissue is fat depot in?
Epicardium
32
Which groove is the coronary sinus, great and small cardiac veins in?
The coronary (atrioventricular) groove
33
What groove is the middle cardiac vein in?
The posterior inter-ventricular groove
34
What part of the heart does the great cardiac vein drain?
Primarily the left atrial and ventricle
35
What part of the heart does the small cardiac vein drain?
The right atrium and ventricle
36
What part of the heart does the middle cardiac vein drain?
The inter-ventricular septum
37
What occurs when chaotic atrial contractions are at faster rates than the ventricles?
Atrial fibrillation
38
What is atrial fibrillation caused by?
Extra electrical impulses disrupting SA node activity
39
First organ to fully develop in the embryo?
The heart
40
Three layers of blood vessel walls?
Tunica intima
Tunica media
Tunica externa
41
What is tunica intima?
Inner simple squamous epithelium forming smooth surface of lumen
42
What is tunica media?
Middle, circularly arranged smooth muscle cells. Responsible for changing vessel diameter. Thickest layer.
43
What is tunica externa?
Outer protective connective tissue layer, strengthens and anchors
44
Order of arteries blood flow?
Blood travels from elastic arteries to muscular arteries to arterioles
45
What are elastic artery characteristics?
Large
Low resistances
High in elastin (tunica media)
46
What are muscular artery characteristics?
Distal
Supplies organs
Tunica media is thicker relative to lumen
smooth muscle sandwiched between 2 elastin layers
Muscular layer regulates blood flow to organ
47
What are arteriole characteristics?
Small
Thin tunica media
Contraction/relaxation regulated via local signals or sympathetic nervous system
48
Three types of capillaries?
Continuous
Fenestrated
Sinusoid
49
What are continuous capillaries?
Most common
| Least permeable
50
What are fenestrated capillaries?
Have pores for high exchange rate
51
What are sinusoid capillaries?
Very leaky for high exchange of large molecules
52
What percentage of blood do all veins carry?
65%
53
Difference between muscle layers of veins vs arteries?
Larger lumen
Thicker tunica externa than media
Less elastin
Thinner walls
54
Two main branches off the ascending aorta?
Right and left coronary artery
55
What do branches of the thoracic aorta serve?
Pericardium
Lungs/bronchi
Oesophagus
NOT the heart!
56
What are the anterior thoracic and upper abdominal wall supplied by?
Branches of the subclavian arteries:
The internal thoracic arteries
57
What three unpaired arteries supply the GI tract and spleen?
Celiac artery
| Super and inferior mesenteric artery
58
Three paired arteries of the abdominal wall?
Supra-renal arteries
Renal arteries
Gonadal arteries
59
What does the superior vena cava receive blood from?
Everything superior to the diaphragm except for the lungs and heart), and drains into the right atrium
60
What does the inferior vena cava receive blood from?
Everything inferior to the diaphragm
61
What vessel receives blood from the heart?
The coronary sinus
62
Three main veins of the head and neck?
Internal jugular
External jugular
Vertebral veins
63
What does the internal jugular receive blood from?
The dural venous sinuses (and most of brain)
64
What does the external jugular receive blood from?
From the posterior and lateral scalp, along with some of the face
65
What do the vertebral veins receive blood from?
The cervical vertebrae and spinal cord, along with superior neck muscles
66
What major six veins does the abdominal portion of the inferior vena cava collect blood from?
```
Lumbar veins
Gonadal veins
Renal veins
Supra-renal veins
Hepatic veins
Phrenic veins
```
67
What two blood supplies does the liver receive?
The hepatic portal vein contains oxygen poor, but nutrient rich blood
The hepatic artery proper contains oxygen rich blood
68
What types of organs does the hepatic portal vein drain from?
Only unpaired organs
69
Difference between hepatic vein and hepatic portal vein?
The hepatic vein carries blood out of the liver, but the portal vein carries blood to the liver
70
What part of the body does the inferior mesenteric vein drain? Where does it receive blood from? (3 veins)
Drains the distal part of the large intestine.
Receives blood from:
- Superior rectal vein
- Sigmoid veins
- Left colic vein
71
What part of the body does the splenic vein drain? Where does it receive blood from? (3 veins)
Drains the spleen
Receives blood from:
- Pancreatic veins
- Short gastric veins
- Right gastroepiploic vein
72
What part of the body does the superior mesenteric vein drain? Where does it receive blood from? (5 veins)
Drains the small intestine and part of the large intestine.
Receives blood from:
- Intestinal veins
- Pancreaticoduodenal veins
- Ileocolic veins
- Right colic veins
- Middle colic veins
73
What do the common iliac veins merge into?
The inferior vena cava
74
What does the great saphenous vein drain into?
The femoral vein
75
What does the small saphenous vein drain into?
the popliteal vein
76
Lymphoid organs?
```
Red bone marrow
Thymus
Spleen
Lymph nodes
Tonsils
```
77
What does the red bone marrow do for the lymph system?
Produce lymphocytes
78
What does the thymus do for the lymph system?
Maturation of T-lymphocytes
79
What does the spleen do for the lymph system?
Monitor blood
80
What do the lymph nodes do for the lymph system?
Monitor lymph and destroy pathogens
81
What do the tonsils do for the lymph system?
Destroy pathogens
82
Primary lymphoid organs?
Red bone marrow and thymus
83
Secondary lymphoid organs?
Lymph nodes, spleen and tonsils
84
What are the functional divisions of the respiratory system?
The conducting and the respiratory zone
85
What are the anatomical divisions of the respiratory system?
The upper and lower respiratory tract
86
Difference between external and nasal cavities?
External is the nasal bone and hyaline cartilage, the internal is the nasal cavity
87
What is the roof of the nasal cavity formed by?
The ethmoid and sphenoid bones
88
What sinuses filter the air in the nasal cavity?
Paranasal sinuses
89
Two type of mucosa membranes in the nasal cavity?
Olfactory and respiratory mucosa
90
What is respiratory mucosa?
Epithelium with goblet cells, function to trap inhaled debris and moisten air
91
What does conchae do to inhaled air?
Filter, heat and moisten air (by cooling conchae)
92
What does conchae do to exhaled air?
Cool conchae take out moisture and extract heat back from air
93
What is the groove inferior to each concha called?
A meatus
94
Three conchae spaces?
Superior, middle and inferior
95
Three sections of pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
96
What closes the entrance to the nasopharynx?
The uvula
97
What type of tissue is found in the nasopharynx?
Pseudo-stratified ciliated columnar epithelium
98
What type of tissue is found in the oropharynx?
Squamous epithelium
99
What type of tissue is found in the laryngopharynx?
Squamous epithelium
100
What does the larynx do?
Connect the laryngopharynx to the trachea
101
Where is the laryngeal vestibule?
Above the vocal cords
102
Where is the laryngeal ventricle?
Between the vestibular and vocal cords
103
What is the opening between vocal folds called?
Rima glottis
104
What are the nine cartilages of the larynx?
```
Thyroid
Cricoid
Arytenoid x 2
Corniculate x 2
Cuneiform x 2
Epiglottis
```
105
What region of the spine does the trachea divide? What is this region?
The Carina - at T4-T7
106
What muscle decreases the trachea diameter?
Trachealis muscle
107
What is responsible for the cough reflex?
The Carina
108
What ligaments connect the cartilage rings of the thorax?
Annular ligaments
109
What type of skin tissue is in the trachea?
Pseudo-stratified ciliated columnar epithelium
110
How do conducting tubes in the lungs differ as they get further into the lung?
Cartilage is replaced by smooth muscle and elastic connective tissue.
Epithelium transition to simple columnar and then to simple cuboidal.
No mucous or cilia in small bronchioles.
111
Difference between type 1 and type 2 alveolar cells?
Type 1 is the gas exchange
| Type 2 produces surfactant
112
What divide lobes of the lungs?
Fissures
113
What is the medial and hilum surface of the lungs refereed to? What about the surfaces facing the ribs?
The mediastinal surface. The costal surfaces are everything else bar the diaphragmatic surface.
114
What do the larger bronchial veins drain blood into?
They collect venous blood and drain into the azygos and hemiazygous systems of veins
115
What type of tissue is pleura?
Serous membranes
116
What is between the parietal and visceral pleura?
Pleural cavity - filled with pleural fluid
117
What is the act of pushing food along the GI tract?
Peristalsis
118
What is the act of churning food in the GI tract?
Segmentation
119
What is the peritoneal cavity?
Between the visceral and parietal layer, it contains fluid to reduce friction
120
What are the two ventral mesenteries?
The falciform ligament and the lesser omentum
121
What are mesenteries?
A double layer of peritoneum that extends from body wall to digestive organs. Holds organs in place, stores fats and is the route for vessels.
122
What are the four dorsal mesentaries?
Greater omentum
Mesentary
Transverse mecocolonm
Sigmoid mesocolon
123
What is the falciform ligament?
Connects liver to anterior abdomen wall and diaphragm
124
What does the lesser omentum connect?
The liver to the lesser curvature of the stomach
125
What does the greater omentum connect?
The greater curvature of the stomach to the posterior abdominal wall
126
What does the mesentary support?
Supports coils of jejunum and ilium
127
What does the transverse mesocolon support?
IT connects the transverse colon to the posterior abdominal wall
128
What does the sigmoid mesocolon connect?
The sigmoid colon to the posterior pelvis wall
129
Four layers of the alimentary canal wall?
Mucosa - innermost
Submucosa
Muscularis externa
Serosa
130
What does the mucosa layer of the alimentary canal wall consist of?
Epithelium, lamina propria and muscularis mucosae
131
What does the submucosa layer of the alimentary canal wall consist of?
Blood and lymphatic vessels along with nerve fibres
132
What does the muscularis externa layer of the alimentary canal wall consist of?
Two layers:
- Circular muscularis - inner layer
- Longitudinal muscularis - outer layer
133
What does the serosa layer of the alimentary canal wall consist of?
It is the visceral peritoneum
134
What is the oral cavity lined with?
Thick stratified squamous epithelium
135
What is the entranceway from the oral cavity to the pharynx called?
Oropharyngeal isthmus
136
What anchors the tongue to the oropharynx?
The palatopharyngeal arch
137
What anchors the tongue to the soft palate?
The palatoglossal arch
138
What is the space between the teeth and lips called?
oral vestibule
139
Three types of projections of mucosa on the tongue?
- Filiform - roughened surface
| - Fungiform and vallate papillae - tastebuds
140
What does ingested food become in the stomach?
Chyme
141
Four regions of the stomach?
Cardia
Fundus
Body
Pyloric
142
Is the duodenum retroperitoneal or intraperitoneal?
Retroperitoneal apart from the most proximal part which is intraperitoneal
143
What does the bile duct enter the wall of the duodenum at? What is the major opening in the duodenum called?
The hepatopancreatic ampulla, which opens into the major duodenal papilla.
144
What is the intraperitoneal of both the jejunum and ileum suspended by?
The mesentery proper
145
What does the ileum absorb?
Vitamin B12, salts and all products of digestion not absorbed by the jejunum
146
What is the valve between the caecum and ileum called?
the ileocecal valve
147
What are the circular folds of the small intestine called? Are they in each section?
Plicae circulares. They appear in the duodenum and jejunum but are far less common in the ileum.
148
What do plicae circulares branch into?
Villi, and furthermore microvilli
149
What are intestinal villi covered by?
Simple columnar epithelium of enterocytes
150
What are the ridges inside the stomach called?
Rugae
151
What does the appendix do?
Contains lymph nodes to neutralise pathogens
152
Two flexures of the large intestines?
Hepatic and Splenic
153
What parts of the large intestine are intraperitoneal?
Caecum
Appendix
Transverse colon
Sigmoid colon
154
What parts of the large intestine are retroperitoneal?
Ascending colon
Descending colon
Rectum
155
What is the anal canal lined with?
Stratified squamous epithelium
156
What does the caecal sphincter prevent?
Back-flow into the ileum
157
What cells are very prominent in the large intestine? What are the hollows called?
Numerous goblet cells
Contain intestinal crypts - simple tubular glands
158
What are the large intestines lined with?
Simple columnar epithelial tissue - small amount of nutrient absorption
159
What are the three special features of the large intestine?
Teniae coli
Haustra
Epiploic appendages
160
What are teniae coli?
Thickening of longitudinal muscularis, with three longitudinal strips
161
What are haustra?
Sections puckered by teniae coli
162
Two main diseases of the digestive system?
Celiac disease
| Crohns disease
163
What is Crohns disease?
Inflammatory bowel disease (chronic)
Body's immune system attacks the bacterial antigens located within the GI tract, causing ulcers and what not.
164
What organs receive blood from the celiac trunk in the GI tract?
Organs above the transverse mesocolon
165
What organs receive blood from the mesenteric arteries in the GI tract?
Organs below the transverse mesocolon
166
The celiac trunk is a branch of the abdominal aorta that supplies all organs which are located ____ and above the ____?
Intraperitoneally and above the transverse mesocolon
167
What organs are located above and below the transverse mesocolon? What does this mean for their blood supply?
The superior parts of the pancreas and duodenum are supplied by the celiac trunk, the inferior sections by the super mesenteric artery.
168
What are the main accessory organs of the digestive system?
```
Teeth
Tongue
Salivary glands
Liver
Gallbladder
Pancreas
```
169
What stimulates the release of pancreatic juices?
CCK
170
What percentage of a body's blood is in the liver?
25%
171
Three main functions of the liver?
Secretion
Hematological regulation
Metabolic regulation
172
What are the endocrine cells of the pancreas?
The islets of Langerhans
173
Are kidneys retro or intra peritoneal?
Retroperitoneally (posterior to peritoneum)
174
What region of body are kidneys in?
Lateral to T12-L3
175
Which kidney is lower?
The right one
176
What ligament holds the kidneys?
They are not attached to any ligaments, instead they are mainly held in position by their pararenal fat capsule
177
Which renal artery is longer?
The right is much longer than the left
178
What percentage of systemic output reaches the kidneys? Via what artery?
1/4th via the renal artery
179
What vein do kidneys drain into?
The renal vein and then to the inferior vena cava
180
Flow of blood through the kidneys?
```
Renal artery
Segmental artery
Interlobar artery
Arcuate artery
Cotrical Radiate (interlobular) artery
```
181
Which artery is between the renal pyramids?
Interlobar artery
182
Two components of the nephron?
The renal corpuscle and the renal tubule
183
What is the renal corpuscle?
The first part of the nephron where filtration occurs
184
What is the renal tubule?
The long, tubular section of the proximal tube, loops of Henle, distal tubule and collecting duct.
185
What are all molecules secreted by the nephrons into urine from?
The peritubular capillaries
186
How much fluid does the glomerulus filter?
1L every 8 minutes
187
What vein and artery separate the renal cortex and medulla?
The arcuate artery/vein
188
Are ureters retro or intra-peritoneal?
Retroperitoneal
189
Three layers of the ureters?
Innermost:
- Mucosa
- Muscularis
- Adventitia
190
Two layers of muscularis in the ureters?
Inner longitudinal
| Outer circular
191
Via what action do the muscularis layers of the ureters propel urine?
Peristalsis
192
What is the adventitia layer in the ureters?
Areolar connective tissue which anchors the ureter to the posterior abdominal wall
193
Three layers of the urinary bladder?
Innermost:
- Mucosa
- Thick muscularis layer
- Fibrous Adventitia
194
What is the muscularis layer of the urinary bladder referred to?
The detrusor
195
What are the parasympathetic axons of urination?
Pelvic splanchnic nerves
196
What is the smooth triangular region of the bladder called? What is it comprised of?
Trigone - two ureteral openings and the internal urethral orifice
197
What segments of the spinal cord do the sympathetic and parasympathetic divisions come from for the bladder?
Parasympathetic - S2-4
| Sympathetic - T11-L2
198
Three main sections of the male urethra? How long is each section?
Prostatic (2.5cm), membranous (2.5cm) and spongy urethra (15cm)
199
What is the erectile tissue in the penis called?
Corpus spongiosum
200
What duct transports sperm to ejaculatory duct?
Ductus deferens
201
What are the blood vessels of the spermatic cord?
Testicular artery, testicular veins
202
What cools the spermatic cord?
Pampiniform plexus
203
What does the superior portion of ductus deferens run through?
The inferior canal
204
What is the spermatic cord nerve?
The testicular nerve
205
What is the deep inguinal ring? When do the testes complete their descent through here?
Entrance to the inguinal canal. The descend to the deep ring by the 3rd month of development.
206
What is the superficial inguinal ring?When do the testes complete their descent through here?
Exit from the inguinal canal. Provides exit for testis to scrotum. The testes complete their descent into the scrotum through the inguinal canal in the 7th to 9th testes month.
207
What is the skeletal and smooth muscle of the scrotum? Main difference?
Skeletal - cremaster muscle
Smooth - dartos muscle
The dartos muscle contracts the skin of the testes (smooth muscle); the Cremaster muscle controls the distance of the testes from the body
208
What does involuntary contraction of the dartos muscle do?
Causes wrinkles on scrotal surface to prevent heat loss
209
What suspend the testes in the scrotum?
The spermatic cord
210
What are each testis covered by?
A visceral layer of tunica vaginalis testis and tunica albuginea
211
Two main cell types of testes?
Sertoli and Leydig cells
212
What does Sertoli cells produce?
Sperm
213
What do Leydig cells produce?
Testosterone
214
What stores matures and sperm for ejaculation in the testes?
Epididymis
215
What is the site of spermatogenesis?
The seminiferous tubules
216
What are seminiferous tubules packed into?
Tunica albuginea
217
What collect sperm form the seminiferous tubules?
Straight tubules
218
What collect sperm from the straight tubules?
Rete testis
219
What carry sperm to the epididymis?
The efferent ducts
220
What form the ejaculatory ducts?
The ductus deferens and the seminal vesicles merging together
221
What glands secrete seminal fluid?
The seminal vesicles, prostate gland and bulbourethral glands
222
What is seminal fluid?
Alkaline fluid that mixes with sperm cells to form semen
223
What do seminal vesicles secrete?
A viscous fluid of fructose prostaglandins
224
What part of semen dilate the cervix?
Prostaglandins (fructose of sperm)
225
What does the bulbourethral gland secrete?
A viscous mucus that protects the urethra and serves as a lubricant during sexual intercourse
226
What does the prostate gland comprise of?
Tubuloalveolar glands
227
What is the term for foreskin?
Prepuce
228
What does corpus spongiosum cover?
The spongy urethra, posterior surface of flaccid penis and the expanded distal end (glans penis)
229
What is the corpora cavernosa?
Paired masses, anterior surface of flaccid penis. (make up most of it)
230
What does the internal urethral sphincter do in males?
Stops semen from back flowing into bladder and prevents the simultaneous passage of sperm and urine through the male urethra
231
Terms for eggs?
Gametes: oocytes
232
What is the only intraperitoneal sexual organ in the body?
The ovary
233
What ligament anchors the ovary to the body wall?
The broad ligament
234
What anchors the outer layer of the uterus?
The ovarian ligaments
235
What ligament attaches to the lateral edge of each ovary and projects superolaterally to the pelvic wall?
The suspensory ligament
236
What is the part of the broad ligament covering the ovary at the hilum?
The mesovarium
237
What are the three layers of the uterus?
Ovarian epithelium
The tunica albuginea
Cortex + Medulla
238
What is the outermost layer of the ovary called?
The ovarian epithelium (or germinal epithelium)
239
What is the connective tissue below the ovarian epithelium called?
The tunica albuginea
240
What does the ovarian cortex consist of?
Ovarian follicles
241
What does the ovarian medulla consist of?
Blood vessels, lymph vessels and nerves
242
What is ovulation?
Release of the ovum
243
What is the uterine (fallopian) tubes surrounded by?
Mesosalpinx
244
Where does fertilisation occur?
In the fallopian tubes
245
Four parts of the uterine tube?
Fimbriae
Infundibulum
Ampulla
Isthmus
246
Three layers of fallopian tubes?
Mucosa
Muscularis (inner circle and outer longitudinal layer)
Serosa
247
Three walls of the uterus?
Perimetrium
Myometrium
Endometrium
248
What layer of tissue does the embryo burrow into in the uterus?
The endometrium
249
What are the two layers of the endometrium? What is the difference?
The functional layer and the basal layer (doesn't shed)
250
What three ligaments hold the uterus in place?
Mesometrium
Cardinal ligaments
Round ligaments
251
What tissue lines the vagina?
Stratified squamous epithelium
252
What does the projection of the cervix into the vagina create?
An anterior and posterior fornix
253
What are the three coats of the vagina?
Adventitia (fibrous)
Muscularis
Mucosa
254
What does the mucosa of the vagina consist of?
Lamina propria and stratified squamous epithelium
255
What is mons pubis?
The skin and subcutaneous connective tissue overlying the pubic symphysis
256
What is the externa genitalia of a female called?
Vulva
257
What are the folds of the vagina called?
Labia majora and minora
258
What glands are found in the female labia?
Sebaceous glands and melanocytes in the minora
259
What is the space between the labia minora called? What does it house?
The vestibule - houses opening to urethra and vagina
260
What is the female equivalent of corpus cavernosum?
Crus of clitoris
261
What is the female equivalent of the corpus spongiosum?
Bulb of vestibule
262
What is prepuce?
A fold of labia minora covering the clitoris
263
What is the perineum in the vagina?
The region between the pubic arch and coccyx
264
What is prolactin and oxytocin responsible for?
Prolactin stimulates production of breast milk, while oxytocin is responsible for milky ejection
265
What is the nipple surrounded by?
Areola
266
What ligaments provide support to gland tissue? (breast)
Suspensory ligaments
267
What ducts drain milk from lobes to sinus?
Lactiferous ducts
268
What are the sinuses at the end of ducts near the nipple? What do they do?
Lactiferous sinuses - store milk
269
What is the feature in the cerebellum thatits between the wo hemispheres?
The vermis
270
What are the folds of the cerebellum called?
Folia
271
What is the space ebtween the vertebral column and spinal cord?
Epidural space
